How to Fixing a heated rear window

Modern heater elements

Rear window heaters fitted by manufacturers are printed on to the surface of the glass or stuck on with special adhesive. Small breaks in an element can be repaired with special conducting paint. One of the most common and simple problems is a blown fuse. Find the fuse protecting the heated rear window circuit.

There are a number of possible causes for a rear window heater not working, including a blown fuse, a broken or chafed wire, a faulty switch, a damaged heater element or a bad earth connection.

Modern heater elements

One of the most common and simple problems is a blown fuse. Find the fuse protecting the heated rear window circuit . On heaters fitted by the car manufacturer, the fuse is perhaps within the fusebox and protects other circuits too. After-market heaters have an in-line fuse fitted between the pick-up point for the live feed and therefore the window heater switch.

Old heater elements

The older heater elements were built into the glass, so if you find any breaks in this sort of heater there is no way of repairing them other than fitting a complete new screen. In this case, it is cheaper to fit an aftermarket heater to the existing screen.

Fuse check

Examine the fuse to see if it’s blown. If it has, replace it and test the heater again: If the new fuse blows as soon because the heater switch is operated, there’s a brief circuit either within the switch or in wiring and you’ll need to check the switch and along the length of the wire to seek out it.

If the fuse looks intact, it’s still worth replacing it to ascertain if that solves the matter. But if the heater still fails to figure, you’ll need to test the circuit with a test lamp.

Repairing heater element with conductive paint

  • One possible cause for the heater not to work is a break in an element. Check each element for signs of a break.
  • Thoroughly clean the glass round the break, taking care not to damage the element further.
  • Stick down some masking tape along each side of the broken element, along the length you intend to repair.
  • Apply a coat of conducting paint to the break. Leave it to dry for 20 minute, then apply a second coat. Remove the masking tape.

Test lamp check

Clip the lamp to an honest earth point and probe the input side of the fuse. If the lamp fails to light, check the wiring between the battery and fuse for breaks or loose connections. If the lamp lights, next check for current at the switch input terminal. If the lamp fails to light, check the condition of the wiring between the switch and therefore the fuse.

Checking the relay

  • If your rear window heater was fitted by the car manufacturer, its electrical circuit will probably contain a relay — a small square or rectangular box usually located near the fusebox. To test that the relay is working, place your fingers on the relay box and operate the heater switch. The relay should vibrate or click. If it does not, it has failed and should be replaced.

If the lamp lights, touch the probe against the output terminal and turn the switch on. If the lamp now fails to light suspect a faulty switch. look for signs of burning round the switch and check that it’s not sloppy in operation. If the switch is faulty, fit a new one.

If the switch is working, next check between the switch and therefore the heater element. Disconnect the wire where it joins the heater element and probe the wire with the test lamp. If no feed is clear trace the route of the wire back along the car and probe it at various intervals until you discover the break or loose connection within the wire.

Element earth

If current is reaching the heater element, check the element earth wire. make sure that the earth connection is clean and tight, which the wire isn’t broken. If you see any corrosion round the earthing point, disconnect the wire, clean it off with wet-or-dry paper and smear vaseline over the world to stop further corrosion.

Heater element

If you still cannot trace the fault, the problem must lie in the heater element itself. Look carefully at each element strip for any breaks. If you are doing find an opportunity in one of the strips, you’ll be ready to repair it counting on the sort of heater.

Older heaters have their elements fitted inside the windscreen glass and in this case the heater can be replaced only by fitting an entire new window. Instead it’s cheaper and more convenient to suit an after-market heater. Modern heaters have the weather printed, or stuck, on to the screen with adhesive. they will be repaired employing a special conducting paint, which is out there from accessory shops.

The benefits of heated windows

While you can’t prevent environmental elements from occurring, snow and ice can be combatted by heating the windows. Air blowing on the within of the glass can be effective if the air is already warm, but it can take quite while to heat up in freezing temperatures. Often, you won’t want to attend that long to begin driving.

Even if the temperature outside is above the melting point, the within of the windows can overcast from moist, humid weather . Foggy windows obstruct your vision very similar to ice and snow on the windows can, making it unsafe to drive. Nearly all back windows on cars and SUVs are equipped with heated windows, and a few trucks are also . The grid on the car window is understood as a car window defogger. it’s a skinny electrical element that power runs through. The resistance within the element causes it to heat up, which warms the glass. the warmth melts alittle amount of ice and snow, and clears the fogginess from the car window .

Immovable side windows and power mirrors on some vehicles, also as a get few windshields, are now equipped with an electrical grid of an equivalent nature. While car window defogger grids are usually visible as long horizontal lines on the glass, the side windows, windshield, and power mirrors use a really fine element that’s barely visible in the least , even on close inspection.

How heated windows work

Heated windows operate on a button or switch, and utilize a timer to turn the heat off after a certain period. Typically, it’s between 10 and 15 minutes of operation.

The rear defogger will pack up if the grid is broken and is that the most common problem for car window defogger grids. If the rear window defogger has an electrical contact come off or a defogger line is scratched through, there’ll not be electrical continuity to heat the rear window. The grid are often repaired and electrical contacts can sometimes be re-secured.


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