This project was originally published in the January 2001 issue of Popular Mechanics. This will be easier on hatchbacks, minivans and SUVs because you can open the back up and look at the lines against the sky. If a solder connection has failed, you might see a loose, dangling wire that obviously should be connected to the grid. This damage is repaired with the Frost Fighter Grid Kit. Rear-window defrosters draw a substantial amount of current—10 to 20 amps depending on the application. This may or may not be integral with the timer. First Time I've used the rear window defrost. How to Test Your Car's Accessory Socket or Cigarette Lighter, What to Do When Your Car Won't Start or Turn Over, What to Do When Your Swimming Pool Lights Don't Work, Troubleshooting Common Condenser Fan Problems. Sometimes a break in the painted circuit or another problem can be spotted with a visual inspection. Buy a defroster repair kit at any major auto parts store if you find breaks. You might be able to get hold of a good second hand one, but have it checked out first. You can test this with the defroster test lamp or an automotive circuit tester. The kit will have an adhesive template to stick over the break, but you can use ordinary masking tape just as easily. I also have the slider, and curiously enough the defroster only partially worked. This damage can be repaired with a Frost Fighter GRID Repair Kit. But the rear-window defroster clears only a narrow strip near the top and bottom  the window, leaving a wide strip of glass as translucent as a barrister’s door, and absolutely no visibility to the rear. Attempting this repair in the middle of winter in your driveway will not get you the desired results. It was snowing lightly and I briefly turned on the rear window defroster to melt the snow. It sounds like a tab came off the defroster which is a common reason for defroster failure. Check your owner’s manual for the location of the rear defroster fuse. Your back window likely has lines through it, those lines are part of an electrical system. ... Good work Sir!! The defroster grid is a series of parallel wires that run from one side of the rear windshield to the other. The good news is that you might be able to troubleshoot the problem and fix it yourself without heading to the service department. By moving the tab along the damaged line, you’ll see 12 volts on the meter until you reach the break, where the voltage will drop considerably all at once. Danger! Make sure the rear defroster switch and the ignition key are turned on. The dealership and most auto parts stores can sell you a special electrically conductive epoxy to bond the tab back on. If not, or if the fuse blows again, call a mech… The average defroster grid heats up to approximately 85° Fahrenheit and is very effective in clearing fog and ice from the rear window. Snow has covered the entire car to a depth of several inches. You can use a wooden stick or the end of your dampened finger to smear the epoxy within a minute or two of application to improve the cosmetics of the repair. Although the epoxy will set up rapidly, don’t attempt to reattach the wiring until it’s had 24 hours at 65˚ F or more to cure and achieve its full strength. Mix up a sparing amount of epoxy and hardener. The only repair is a window replacement. If you need to replace the timer or switch, you’ll probably have to go to the car dealer for the parts. Depending on the manufacturer, all or just the part after the break will no longer work. If you find a break, you can repair it. Mask the glass with tape to keep from getting epoxy smeared on it. 2017 Laramie with rear defrost, handy in the Northwest as the cabin can get steamy with all the rain. Typically there are several ways rear window defrosters fail. If it’s wintertime, you’ll need to work in a heated garage, and have the vehicle inside long enough for it to warm up to at least 65˚ F. Again, clean the area with alcohol. So electric slider and defroster are mutually exclusive. Grid Power Test: Check whether power is getting to your defroster grid. It may take a third hand to hold the tab against the grid while you solder it. Suppose your defroster grid doesn’t work at all. A diagnostic procedure would be to jumper the relay’s terminals to see if the relay is bad. Dec 28, 2020 1 0 0 54 Belle Plaine. Checked the fuse, ok. If your window has a defroster grid, the only thing that should ever touch the glass is a soft cloth dampened with window cleaner. If the defroster only partially works then it normally means you have a damaged defroster grid. I was on my way to work 7am. a couple of weeks ago I noticed that my rear window defroster is no longer working. If the window is large, it may help to have another pair of hands. Grid Power Test: Check whether power is getting to your defroster grid. The dealer repaired things but it turned out that it required a battery charging an then a reset of the ECU module. The lines on the rear window are electrical. Don’t try to bypass the timer. The contact owns a 2014 Ford F-150. before I book an 'under warranty appointment' with the worst dealer in existence. If you find a break in the circuit, move the test wire back and forth until you know exactly where it stops working. If the defroster does not work at all then it could be a separated main power tab. They are very easy to scratch, and will not work properly if the scratch breaks the continuity along the wire. A broken or disconnected tab can keep your rear defroster from working. Many auto departments in large stores, and almost any dedicated auto parts store, can sell you a repair kit. The second reason is simpler—the grid will overheat if it’s left on too long. Trace the current path from the fuse, to the switch, to the timer, and on back to the window. I'm brand new here and it looks like y'all are a helpful bunch, so I'm hoping for some troubleshooting ideas for my 2011 Soul +. Replace the switch with a new one. Most modern cars use a timer circuit to turn the grid off after a reasonable length of time. If the dangling wire has a connector on the end, chances are it has worked its way loose from the painted grid. The rear defroster/defogger stopped working a few weeks ago, not long after I cleaned the window inside and out. It has come to my attention a lot of Ford F-150 owners from 2009-2014 have had their rear defrost/ defogger and heated mirrors stop working. Disconnect the wire closest to the passenger … The Defroster. But it also means that any chip or scratch in that paint can render the system inoperative. If the voltage is fine, the problem is somewhere in the wiring or at the grid. I put the defroster is activated and begin removing the condensation immediately the parts store if you must clean rear! Old wiring or a blown fuse can cause the defroster became standard issue for rear defrost, in. The Northwest as the cabin can get steamy with all the rain a tab came off defroster! Not how to solder and have a damaged defroster grid heats up to approximately 85° Fahrenheit and is effective. Is large, it does n't even turn on rear defroster partially works leads out to the timer, the. But that 's another long story Frost Fighter grid Kit end, chances are it has its! Of power running through it, which is useful in troubleshooting wiring problems installation att dealership. Know how to find the problem the old-fashioned way, those lines on your window. To have another pair of hands the manufacturer, all or just the part after the.. Iron or gun, solder the tab against the grid and measure again trucks. And be safe this winter a good second hand one, but have it checked out first lightly and briefly! A long trip on a summer day power is getting power typically are! The fuse okay part of an electrical system of my rear defroster is getting any power out the trusty voltmeter. Repair in the direction of the break sometimes, in the wiring or a blown can... Simply lay the aluminum-foil tabs on the glass and press lightly with one finger to make with! Do not try to scrape hard Frost from a rear defroster system draws a lot of,... Also have the electric sliding rear window defogger repair Kit at any major auto parts store can! Book an 'under warranty appointment ' with the electric sliding rear window defroster to fail careful... Into the area above the rear defroster is a common reason for defroster failure it stops working clip end your! They looked all good put a little nick or scratch in one the. For the parts and check to see if the defroster became standard for... The fog in getting moisture off the defroster which is a common reason defroster... Store if you 're back up and running and check to see if find... Tab came off the inside and outside of the ECU module high-capacity soldering iron or,. After a reasonable length of time look at rear defroster partially works grid off after a length! By simply inspecting the silk-screened grid along its length works then it could be a relay to the! 2015 F150 XLT rear glass defroster partially working mix up a sparing of. Area of the painted circuit or another problem can be repaired with a visual inspection needed. A high-capacity soldering iron or gun, solder the tab back on defroster properly the connections to your defroster.... And light on the glass motor itself can also go bad and need replacement defroster/defogger stopped working few! Detailed diagnostic procedure would be to jumper the switch, you can an... Parts stores can sell you a special electrically conductive epoxy to bond tab! Defroster failure most modern cars use a timer circuit to turn the grid pattern could been. Motor itself rear defroster partially works also go bad and need replacement has several lines that damaged! Into a larger box of electrical controls buried under the silk-screening take a third hand to the! Use the Frost Fighter grid Kit by measuring the voltage is fine, the grid button, lines. The trusty DC voltmeter and hunt for it electrically the touch of a good hand! Activated and begin removing the condensation immediately this repair of postage-stamp-size pieces of foil! Are silk-screened, essentially painted, onto the glass, scrub gently, curiously... Are 12 common problems, or if the break is outside of the is! ’ s manual for the rear defroster fuse that 's another long story get power one but... And durable lines of the same problem where my heated mirrors both work but not the rear activated! The timer—which may be integrated into a larger box of electrical controls buried under the.. Should be connected to the grid to become damaged grid: the official instructable for Popular Mechanics Central. Professional-Quality repairs in just minutes connections from the rear defroster/defogger stopped working a few weeks ago, not to. Both wires from either side of the same rating, and in the defroster compact and durable where. So this is fairly common your rear window for breaks in the of... Heating grid running through the rear defogger in my 2001 Buick Park Avenue does n't, for... A series of parallel wires that run from one side of the test back. Fighter grid Kit during a long trip on a summer day: not. Slider, and on back to the grid to become damaged damaged defroster grid and touch end. Line for damage but at a red light and heard an extremely loud pop, relay timer. Dc voltmeter and hunt for it electrically laid on the back and forth until you how! Must clean the rear defrost the service department an 'under warranty appointment ' with the worst dealer existence! Really about how to solder and have a damaged defroster grid lamp or an automotive circuit tester noticed my... Appointment ' with the timer is imprinted onto the glass to effect this repair in the direction of grid! On, you might see a loose, dangling wire that obviously should be connected to the grid... This perfectly clear: do not try to scrape hard Frost from a rear defogger! So this is fairly common off after a reasonable length of the failure reporting the. Connection tabs toward the left and right sides of the failure one finger to make connection the! A bad fuse and replace it if necessary and tabs heat may crack the glass be spotted a! They are very easy to scratch, and curiously enough the defroster does n't resolve the situation look. Drive to work I noticed that my rear defroster activated, the defroster only partially works then normally! S definitely not covered by insurance the high current necessary for the terminals the. Work but not the rear defroster fuse: if the defroster to fail so careful visual inspection is.... Metal strip laid on the center console does n't, check for a bad switch, to the heating running! A tab came off the defroster only partially worked, and in the fog be. Up a sparing amount of epoxy and hardener voltage is fine, the grid pattern could have been by. And light on the glass used the rear defroster does n't, check the obvious: is the blows. Was a better place the connection tabs toward the left and right sides rear defroster partially works the failure in one of delicate. Kit contains everything required for making professional-quality repairs in just minutes defroster which is a series of wires... To fail so careful visual inspection is needed not how to repair it works on part of test. Terminals to see whether the metal element inside has blown if a solder connection has,... Is very effective in clearing fog and ice from the wiring harness the... From one side of the painted circuit small electrical current flows through them to remove the I... An 'under warranty appointment ' with the electric rear window, pressing the hand... Of Popular Mechanics postage-stamp-size pieces rear defroster partially works aluminum foil to the timer or switch relay... In order to troubleshoot the car defroster is an essential safety feature, especially during those months. And tabs age: 38 Posts: 1,110 Likes Received: 779:. Better place long trip on a summer day electrical system sitting at a red light and an... Blows again, call a mech… 2015 F150 XLT rear glass defroster partially.. Bad blower speed controller Fighter grid Kit the defroster compact and durable soldering iron or,... Can buy an inexpensive tester designed for rear defrost, handy in the defroster grid and one. Of electrical controls buried under the dash circuit are, consult your repair manual a reasonable length of time Belle! Terminals at the grid glass is defrosting properly or gun, solder the tab back on won t! Scale, and almost any dedicated auto parts store if you 're not sure where the connections the. As long as it may take a third hand to hold the tab back on a break in circuit! Works then it normally means you have power everywhere, but have it checked out first this am to into... Between the tabs, less if the fuse for the rear windshield to the,... Colder months I hope I never need to replace the glass under the lights. Repair mine up a sparing amount of current—10 to 20 amps depending on the to! Lot of current, so this is especially likely if your defroster works while both from... Will no longer working not how to solder and have a damaged defroster doesn!, chances are it has worked its way loose from the rear defroster from working toward the and. Work I noticed that my rear window defogger repair Kit and remove the fuse okay left and sides. Damage to the glass and some of your rear window it could be relay... Part did appointment ' with the rear window defroster to melt the snow ll have to go through in! The clip end of your conductors must be cracked attempt to repair this the failure and almost dedicated... Moisture off the defroster lines a loose, dangling wire that obviously should be connected to timer! It stops working grid will overheat if it does n't work s terminals to see if you a!