Rear Defroster

[Satch]

when i turn on the rear defroster, it blows the fuse. I checked the harness and connections in the rear door. All good. The light in the switch comes on, don't know if it is suppose to, seeing as the fuse is blown. has anyone any ideas what the problem might be? It is a 99 and otherwise fine! Thanks for any help. Satch

[Gussie2000]

Hey satch !

There's two possible issues.

1 You might using the wrong amperage/volt fuse
2 A short in the wiring line.

The only way you can verify that there's no short is tracing the wiring from the switch all the way to the rear door.

Do this:

Get you self an voltimeter.set the voltimeter to DC 12volts & have it connected to the + & - defroster wires,turn on the defroster & look for voltage fluctuations,if the voltimeter reading screen is jumping from low to high & viceverse then you figured out what is causing the fuse to blow,probably a exposed wire that lose insulation due friction.Also make sure the ground cable is really grounded,it shouldn't be that hard to have it straight.
Another possible solution is to use a fuse with a higher amperage/voltage,but this one should be the last option.


Gustavo

[don moore]

look at the area of the door hinge..

[Satch]

Thanks you guys, i will do as you say. just need time to get to it. i did check the harness in the rear door and all is good. i will look in the front and work back. should the light for the defroster come on, even if the fuse is blown? thanks for your info. Satch 99

[Gussie2000]

Thanks you guys, i will do as you say. just need time to get to it. i did check the harness in the rear door and all is good. i will look in the front and work back. should the light for the defroster come on, even if the fuse is blown? thanks for your info. Satch 99

I'm not sure 'bout the LED light, according to electrical schematics it shouldn't if the fuse is blowed.

However,remove the dash board & look for any weird thing that not seems to be right.

[MSHardeman]

Satch,

I just got done troubleshooting my rear door popper and what I found may also affect your defroster.

If you open the jack cubby on the drivers side of the VX and look at the back wall of the cubby you'll see two disconnects for the wire looms heading from the rear of the VX to the front. The one on the bottom is the loom with the defroster wire, and the license plate lights. If you follow that loom to the back of the VX it should pass through a rubber grommet and that grommet should be seated down in a niche in the metal plate that it passes through. If it isn't then the loom could be in the way of the path of the rear door stop. When you close the door the stop swings into a cavity behind the brake light and passes through a hole in the metal plate that the wire loom passes through. My loom was out of the niche and the stop kept crushing it against the metal plate until if finally cut my door popper wire in half. It had also worn through the wire insulation on one of my wires heading to the door, but luckily I hadn't had any problems yet.

I'm wondering if maybe your wire is frayed and may be shorting out on the metal plate that the loom passes through. I can take pictures of everything that I'm talking about if you think it will help.

Good luck.