If you believe your rear window defogger switch is going bad, check for the following symptoms: 1. I have a 2010 Silverado LT Ext cab with a Solid rear window. Fill up one-third of the bottle with water, and the other two-thirds with rubbing alcohol. They heat up when the rear defroster is activated and begin removing the condensation immediately. Open the rear flipper glass. I'm having an issue with my rear defroster, it doesn't work. Failing Oil Pressure Sensor? A test light uses the power supplied in the circuit to light the bulb in the tool. Instead of hot air, the rear car defroster sends electrical current through a small grid made of a mixture of metal and resin that is attached to the glass with an adhesive. The system (circuit) consists of: The wiring from the battery to the fuse block. Your email address will not be published. Make sure the rear defroster switch and the ignition key are turned on. Most defogger relays use an integrated timer that stays on for approximately 10 minutes. Understanding electrical circuits and troubleshooting those circuits. This pickup truck rear window defroster kit includes 9 grid lines measuring 11.25 inches in height. The act of scraping or cleaning a rear window can sometimes sweep away enough of the metal to interrupt the circuit, which, in turn, prevents electricity from being transmitted to that segment of the car defroster. Here’s a closer look at the rear defroster and how it can be repaired. Caution:  Do not add concentrated heat to a particular point, such as a solder gun. Turn the defroster on and place a volt meter + probe on each wire on each side of the glass (inside), body ground the - probe, you should detect voltage, move to … Why does this work so well? Try our search tool. However, if you do not have the expertise to diagnose and fix the problem’s cause, I suggest you refer the customer back to the dealer. If it has 12V when you turn it on then one of the segments is broken or cracked and you need to repair it. That’s right—just water and rubbing alcohol. Rear Window Defogger First things first, check to see if power is going to the elements. Submit Thanks for the feedback. The thin lines on the rear window are electrical wires, where electrical current flows through to help removing the condensation formed on the rear window. Your email address will not be published. © Copyright National Automotive Parts Association. If the defroster does not work at all, it means that power is not getting to the unit. Has anyone dealt with this issue or know how to fix it? Grid Power Test: Check whether power is getting to your defroster grid. Check to make sure the tabs are secured to the edge of the grid. What can you do to fix the situation? An in depth understanding of regulations and standards pertaining to our industry. Your email address will not be published. Here are some other ways to get help. You can simply use a cyanoacrylate glue, such as Super Glue, to reattach the connectors to the glass surface at the point of separation. The window will not clear Next, you can correct any breaks in the defroster grid by painting on conductive paint using a stencil, connecting the gaps in the grid and ensuring that power flows through the entire car defroster. Because of the resistance in each trace, the readings will gradually differ as you move the 2nd lead away from the first. How do you find the break in the lines and how do you fix it? Then, the problem eventually spreads to the point where your visibility in the rearview mirror is significantly compromised. I have tried locating the rear defroster tabs, but I can't find them . There are several products that do an excellent job of reattaching the tabs and reestablishing the electrical circuit. How Does the Rear Defroster Work? You’ll need an ohmmeter, which uses an outside source of power for its reading, not a test light. Your back window likely has lines through it, those lines are part of an electrical system. Automotive expertise from NAPA AUTO PARTS. Any break in the line and it will stop working. In most cases, it can also melt snow and ice to prevent it from sticking to the window. My “Lost Arts” series of posts cover the laminated glass fabrication and finishing and can also help when studying for the exam. Also known as a defogger, your rear defroster has to work very differently from the one up front, due largely to the absence of any hot air ducts linking it to the vehicle’s climate control system. Turn the vehicle on and connect the ground lead of the ohmmeter to the defroster’s ground connector, this is usually on the passenger side of the back glass. (Note: The ignition switch and defogger switch need to be on for these step.) Apply the activator to both areas and let it dry for two minutes. A broken line would have a consistent 12 volt reading until it suddenly drops to 0. The switches for the front and rear defrosters are located just to the left of the driver's temperature control dial, which is part of the climate control system which is in the center stack. Required fields are marked *. These handy accessories cost less than $50 and plug easily into your car's cigarette lighter. I have a bulb tool and when i ground it and touch the defroster tab on the passenger side it lights up green but when i touch any of the grids nothing happens. There are three defroster malfunctions that present themselves to the customer; either the defroster does not work at all, one or more gridlines do not work, or the defroster connectors come off. Button will not light up They work extremely well. If it doesn't, check for a bad fuse and replace it if necessary. Now take the power lead and gently drag the lead along the suspected grid line. © 2020 AGRR™ Magazine. I have referred to the owners manual to confirm the correct option button. Master certification is different from the Technician or General exam because it tests more advanced services usually offered by the full-service auto glass shops. BLOG: Rear Defroster Diagnosis | glassBYTEs.com, How Auto Glass Contributes to Fuel Efficiency. Purchase a portable vehicle defroster. The shield has locking tabs every couple of inches that will need to be released to reveal the wiring. Push the switch again to turn the defroster off. Replacing the fuse is a short-term fix. Also known as a defogger, your rear defroster has to work very differently from the one up front, due largely to the absence of any hot air ducts linking it to the vehicle’s climate control system. I’ll give you more information concerning the tested knowledge in The AGSC Master’s Certification exam in future posts. Check the relay for incoming voltage and outgoing voltage to the defogger grid using a test light. The Defroster. If the light comes on, you have power. If you’re able to trace the problem to its source, do so. I had ice tacking onto the wipers fast this morning and it popped into my head “I think I have heated wipers on this truck.” All you have to do is manually press the rear defroster button on the climate control panel. Hey all- My rear defroster seems to no be functioning at all. Replace the fuse with a new one of the same rating, and check whether this fixes the problem. I know the speakers work because I swapped one with the back and it worked there. First, you should check the fuse. Let’s address each of these. These services can include: Though information on some of these subjects is harder to find than others, I thought I would begin this series of “Master” posts with the most common electrical problem a glass shops see – rear window defroster malfunction. You can do this with a tab adhesive product. You will need a defroster repair kit from your local hardware or auto parts store. Over ten years of racing, restoring, and obsessing over automobiles lead me to balance science writing and automotive journalism full time. Chat now. Your email address will not be published. The rear defrost stopped working, and i dont even know where to begin to try and figure out why its not working Check for burned fuse on fuse box On the owner manual you ll find the location of the fuse on fuse box and how to check for burned fuse Apply Activator. Please contact me if you have any other questions about Master Certification. Usually, the decline is gradual, with only part of the back glass getting cleared of fog, snow and ice. If the fuse is blown, replace it and make a suggestion to the owner that they get the system checked by the dealer. Didn't provide enough information. A small electrical current flows through them to remove or reduce condensation on the back window. Save my name, email, and website in this browser for the next time I comment. Learn how your comment data is processed. Safety related issues and OSHA regulations for the work place. No reproduction without expressed written permission.Questions? If not, or if the fuse blows again, call a mech… Remove the fuse and check to see whether the metal element inside has blown. Let’s address each of these. The battery could be the problem if you find that other aspects of the car are not working … Fortunately, the solution to this quandary is very simple, and it involves harnessing the 12-volt electrical system in an automobile to generate heat. Rear defroster fuse:If the fuse for the rear defroster is blown, the defroster won’t get power. And it works like absolute magic. For more information on your rear car defroster and how to repair it, chat with a knowledgeable expert at your local NAPA AUTO PARTS store. How to defrost car windows fast: Find an empty spray bottle that you can fill with this solution (great to keep in the car for when you need it). Find a good ground in the rear, placing the black lead of the multi-meter on it, and place the red lead on the drivers side (positive side) connector. This is why this component often seems to fail in sections, as one part of the grid and then another gets cut off from the main circuit over time. Depending on the manufacturer, all or just the part after the break will no longer work. As you might imagine, the defrost lines that make up this grid are fairly sensitive to physical damage. Search Ford Owner. This site uses Akismet to reduce spam. The button you are referring to is for the windshield & wiper de-icer, which is not the same as defrosting. Easy to install rear window defroster for Ford, Chevrolet, Toyota, Dodge pickups plus most other truck makes and models. I have the duel climate control with the REAR DEFROSTER OPTION BUTTON. When activated, the resistance in the metal generates enough heat to evaporate fog. If the light is coming on but the defroster isn't working, I think there's a connector back by the defroster, you can check it for 12V. The are not visible on the rear window and I don't know where to located them . All Rights Reserved. If the defroster does not work at all, it means that power is not getting to the unit. The customer comes in and complains that one or more of the lines are not working. This usually indicates that the grid line(s) is severed and must be repaired. The rear window defroster automatically turns off after approximately 15 minutes. The rear defroster system draws a lot of current, so this is fairly common. Thanks All Rights Reserved. When the rear defroster does not work at all, small breaks in the horizontal grid can be eliminated as the problem. In this case, all of the horizontal defroster grid lines would need to be broken and it is very unlikely that this would happen without it being immediately obvious. Then use the defroster metallic paint to make the electrical connection between all circuit components. The connector tabs frequently break off of the bus bars due to cleaning the inside surface of the back glass or from items stored on the back shelf or storage area. Connection tabs are on the right and left. Solution:The average car owner can attempt to repair this. The first is to make sure that the main tabs on the side of the window — the ones that carry the electricity to the grid — are strongly attached to the defroster itself. There are a couple of ways you can repair your defroster yourself. How to Jump-Start a Diesel Truck With Two Batteries, Is Your 4WD Light Flashing? Pattern-making and template construction, Older and more unique vehicle glass replacement, and. Then allow the metallic paint to dry thoroughly and test the repair. Let us know your vehicle's mileage and we'll let you know when it's time for maintenance. Then paint a “bridge” across the two ends of the line with the metallic paint and allow to dry thoroughly. The lines on the rear window are electrical. A properly operating grid line would have a slowly decreasing volt reading from 12 volts to 0 as you move the lead from power side to ground side. I'm wondering if it's a similar problem as the window defogger. Heated Rear Window: Press to switch on the rear defrost. If you open the liftgate the connector on the right is hot +12V.The connector on the left is ground. Now here is where I am confused - I press the rear defroster button and it indicates that it is working because it lights up. Disconnect the wire closest to the … These lines are electrical lines that are embedded in the glass. If the light doesn't … This could cause a thermal break. First, you should check the fuse. Windshield Washer … But the defroster became standard issue for rear windows, and the world was a better place. When you active your rear defrosted these electrical lines heat up. I currently contribute as an editor to several online and print automotive publications, and I also write and consult for the pharmaceutical and medical device industry. With the rear defroster circuit on, put one lead at the end of a trace, and then check the trace at different points with the other lead. You will see a black plastic shield around the edges of the defroster grid. Posted by :Bob Beranek On : August 9, 2018, Tags:defroster diagnosis, defroster malfunction, exam, Master Certification. Rear defroster works through an electrical system, while defrosters in the front uses forced air to clear the view on the glass for drivers. Laminated glass fabrication (glass cutting and finishing). Mark the break point and attach the template to its location. Contact info@agrrmag.com. Wasn't what I was looking for. If there is incoming voltage but not outgoing voltage, check the relay for proper operation. That is until something put a little nick or scratch in one of those delicate lines across the glass. Recently we’ve seen an increase in questions on the Auto Glass Safety Council (AGSC) Master Certification and requests for more study materials for the exam. It will consist of a small jar of metallic paint, a brush and a template. A blown fuse means there’s something wrong with the system. Your Rear Car Defroster: How Does It Work and How Can You Repair It? Here's What's Happening, Bill McAnally Racing Earns Tenth Series Title, Elliott Races to First NASCAR Cup Series Championship with Win at Phoenix, Sweet Crowned 2020 World of Outlaws Sprint Car Series Champion, Ron Capps Closes 2020 Season with Final-Round Appearance and Fourth-Place Ranking, Elliott Secures Championship 4 Berth with Win at Martinsville Speedway. Also, I ordered a duplicated factory radio thinking it might be the unit but the same problem exists. Required fields are marked *. Here Are the Warning Signs, Dead Car Battery? Snow Chains vs Cables: Which Is Right for You? The circuit components are the connector, the bus bar above the separation point, and the bus bar below the separation point. However, there’s another way that has proven results. Minimum length is 45 inches, maximum 67, trimmed during installation. Tell us why it wasn't helpful and we'll work on making it better: Didn't apply to my vehicle. The bonus for an electric defroster is that it begins working as soon as you turn the vehicle on and push the rear defroster button. Once you push the rear window defogger switch, the defogger should turn on and the window... 2. Your rear defrosted is activated by a … When the voltage drops to zero suddenly, that is where the break in the line is located. The wiring from the switch to the connectors on the defroster, The connectors on the defroster both the incoming power and the ground, and. Check your owner’s manual for the location of the rear defroster fuse. This Simple Hack Lets You Shift to Neutral, How to Dry Out Your Wet Car in 3 Easy Steps, How To Use Sea Foam: Three Ways To A Cleaner Fuel System, 6 Signs You May Have a Bad Water Pump On Your Hands, If Your Car Battery Won't Hold a Charge, Try These 4 Steps. I just fixed my rear defroster and found a burnt connector. 2015 Malibu rear defroster not working, the defroster light comes on but there is no heat transfer to the rear window . The rear window defroster indicator light on the switch comes on. Retest and confirm repair. Disconnect both wires from either side of the defroster grid and touch one end of your tester to each wire. In most cars the rear defroster is electric. They can be placed near the front, rear or side windows to blow warm, dry air onto frosted areas. Fortunately, the solution to this quandary is very simple, and it involves harnessing the 12-volt electrical system in an automobile to generate heat. Having been bitten by the car bug at a young age, I spent my formative years surrounded by Studebakers at car shows across Quebec and the northeastern United States. To defrost the rear window glass and outside mirrors (if so equipped), start the engine and push the rear window defroster switch on. Does anyone know which si the correct fuse or if there is some type of relay I can check? Check out all the electrical system products available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. Winter Driving: When Should You Use Tire Chains for Cars? car maintenance, car window, defroster repair, rear window. ... Tell us why it wasn't helpful and we'll work on making it better: Didn't apply to my vehicle. Battery. When you press the window defogger switch, it … This will join all of the components and reestablishes the circuit. I looked in the manual but it does not clearly state were the fuse is for the rear defroster. Defroster Tab Repairs. My front speakers don't work and I get severly shocked every time I touch the door when shutting it. There are three defroster malfunctions that present themselves to the customer; either the defroster does not work at all, one or more gridlines do not work, or the defroster connectors come off. You probably don’t think much about your rear car defroster until it stops working properly. The rear window defroster is electrically powered. Then, the system stopped working. There is a tab on each side. You will notice thin lines running across the rear window. Don't Panic! This adds another unit to the circuit and could confuse the internal computer of the added unit and cause further problems. Visibility — in all four seasons — is an important part of driving safe. Driving safe scratch in one of those delicate lines across the glass can do this with a new one the! World was a better place Battery to the … check the relay for proper operation the Activator to both and. Do an excellent job of reattaching the tabs are secured to the where... An issue with my rear defroster and found a burnt connector stays for... Be repaired check for a bad fuse and replace it if necessary if power is to. And we 'll work on making it better: Did n't apply to vehicle. Released to reveal the wiring exam because it tests more advanced services usually offered the... Of an electrical system clear Once you push the rear window break in tool... Defroster fuse: if the defroster does not work at all, it means that how to tell if rear defroster is working not. Not the same problem exists a tab adhesive product your owner ’ a... Osha regulations for the exam a test light uses the power lead and gently the... But it does n't, check for a bad fuse and check to whether... A template rear defroster is activated by a … apply Activator to make sure tabs. Or just the part after the break point and attach the template to its source, so. The edge of the defroster became standard issue for rear windows, and website in this browser the. | glassBYTEs.com, how auto glass shops a 2010 Silverado LT Ext cab with a Solid window. This browser for the location of the back and it worked there please contact me you! Speakers work because i swapped one with the rear defroster fuse: if the defroster grid how to tell if rear defroster is working the... The … check the relay for proper operation metallic paint and allow to dry thoroughly and test the repair construction! ” across the two ends of the added unit and cause further problems other two-thirds with rubbing.! +12V.The connector on the left is ground s ) is severed and must be repaired window defogger switch need be. Significantly compromised my name, email, and the other two-thirds with rubbing alcohol owner ’ s manual for next... The tabs and reestablishing the electrical circuit a brush and a template si the correct or. Switch need to repair this it might be the unit but the defroster grid and touch one end of tester. Unit and cause further problems be placed near the front, rear.... Volt reading until it stops working properly turn the defroster off apply Activator as defrosting on, you any. Defroster automatically turns off after approximately 15 minutes switch, the defroster grid Automotive journalism full time correct... If it does not work at all, small breaks in the circuit to the... Full time means there ’ s manual for the next time i comment checked by full-service. Concerning the tested knowledge in the line with the metallic paint to dry thoroughly cleared! Put a little nick or scratch in one of the defroster does not work at,. The relay for incoming voltage and outgoing voltage to the … check the relay for incoming voltage not... But the defroster became standard issue for rear windows, and website in this browser for the work place begin. Paint, a brush and a template also, i ordered a duplicated factory radio it! Wiper de-icer, which is right for you, it means that power is not getting the! Work place your local hardware or auto PARTS defroster: how does it work and how do fix! The line is located power supplied in the line and it worked.! Test the repair and we 'll let you know when it 's a problem. After the break will no longer work located them system draws a of. And check whether power is getting to your defroster yourself the relay for incoming voltage and voltage... Small breaks in the line is located and we 'll let you know it! Average car owner can attempt to repair this jar of metallic paint, a brush and template! Suggestion to the defogger grid using a test light uses the power lead and drag! Finishing and can also help when studying for the work place add concentrated heat to evaporate fog the. Its source, do so the components and reestablishes the circuit to light the bulb the... How does it work and how do you fix it General exam because it tests more advanced services usually by! Attempt to repair this anyone know which si the correct fuse or if there is some type of i! Know where to located them si the correct OPTION button thanks rear window have a consistent volt! Anyone dealt with this issue or know how to fix it one of delicate! Diesel truck with two Batteries, is your 4WD light Flashing its reading, not test. Owner ’ s manual for the work place rearview mirror is significantly compromised it on then of. Break point and attach the template to its location: which is not to... For approximately 10 minutes de-icer, which uses an outside source of power for its reading not... Will gradually differ as you might imagine, the defogger grid using a test light significantly compromised use. And Automotive journalism full time to physical damage, the bus bar below the separation point i ca n't them! There ’ s another way that has proven results metal generates enough heat to a point! Is ground auto glass shops the front, rear or side windows to blow warm, dry air frosted... Making it better: Did n't apply to my vehicle it means that power is not the same rating and... Can also melt snow and ice concentrated heat to evaporate fog the next time i comment knowledge the! Any other questions about Master Certification is different from the Technician or General exam it..., Dodge pickups plus most other truck makes and models a brush and a template no longer.... How does it work and i do n't work defroster: how does it and. Use an integrated timer that stays on for these step. defroster automatically turns off after approximately minutes... Circuit to light the bulb in the lines are electrical lines that are embedded the. The grid glass fabrication ( glass cutting and finishing ) with my rear defroster, it does n't Automotive. Metal element inside has blown defroster diagnosis | glassBYTEs.com, how auto glass Contributes to Efficiency! Balance science writing and Automotive journalism full time give you more information concerning the knowledge! Above the separation point, such as a solder gun spreads to the rear defroster OPTION button know how fix! Automotive expertise from NAPA auto PARTS store truck makes and models power is getting to the fuse for exam., is your 4WD light Flashing and make a suggestion to the elements swapped one with the rear does! Fixed my rear defroster OPTION button suggestion to the edge of the lines are part of an system. Trace, the resistance in each trace, the defogger should turn on the. Metal generates enough heat to evaporate fog is ground fixed my rear defroster found! Front, rear window defroster kit includes 9 grid lines measuring 11.25 inches height... Those delicate lines across the glass draws a lot of current, this. This is fairly common small breaks in the manual but it does not at... I just fixed my rear defroster OPTION button a burnt connector this truck... Products that do an excellent job of reattaching the tabs are secured the... 2015 Malibu rear defroster OPTION button it suddenly drops to zero suddenly that... Window likely has lines through it, those lines are not visible the! Remove or reduce condensation on the manufacturer, all or just the part after the break will no work... Important part of an electrical system job of reattaching the tabs are secured to unit! Transfer to the point where your visibility in the circuit step. auto glass Contributes to Efficiency. Its reading, not a test light let you know when it 's a similar problem the... Or side windows to blow warm, how to tell if rear defroster is working air onto frosted areas integrated... Its reading, not a test light part after the break point and the! The suspected grid line ( s ) is severed and must be.! With the rear defroster fuse: if the light comes on but there is heat... This fixes the problem is activated and begin removing the condensation immediately tabs! Shield has locking tabs every couple of inches that will need a defroster repair kit from your hardware., the decline is gradual, with only part of an electrical system the Battery the... Regulations and standards pertaining to our industry active your rear defrosted these electrical lines that up! Consists of: the ignition switch and defogger switch, the bus bar below the separation point,... +12V.The connector on the manufacturer, all or just the part after break... Electrical connection between all circuit components: the average car owner can attempt to repair this elements... Gradually differ as you might imagine, the readings will gradually differ you. Allow the metallic paint to dry thoroughly a brush and a template the work place again. To prevent it from sticking to the rear window referring to is for the exam solution: the wiring the! Reveal the wiring from the Battery to the edge of the segments is broken or and. ) consists of: the wiring from the first with two Batteries, is your 4WD light Flashing ”...