Rear window defroster not working? Why? - Third Generation F-Body Message Boards

johnblacksox · 11-02-2009, 07:24 PM

The switch for my rear window (hatch window) defogger isn't working right.

Normally, you put it on, it stays on for like 5-10 minutes, then goes off.

Now, I have to push it like 10 times before it goes on, and even then, it goes off again after about 20 seconds.

I have an 86 SC. What do you think the problem is? Switch? Wiring? Contacts in the back?

If it's switch or wiring, are replacement parts available, or am I doomed to have a permanently foggy and icy back window?

Thanks!!

dirtyd6669 · 11-02-2009, 08:45 PM

i would check all the wires first but it sounds like the switch is going on it. i would look at junkyards for a used switch since there cheap there

ellocojorge · 11-02-2009, 10:09 PM

thats the same thing mine does, it turns on but shuts off after a couple of minutes

1ATony · 11-03-2009, 09:58 AM

Also make sure the two wires from the defrost grid are connected to the tabs on your hatch struts.

It's probably the switch,but I'd check everything.

camaronewbie · 11-03-2009, 10:43 AM

can usually find switches on eBay as well

johnblacksox · 11-03-2009, 10:14 PM

Quote:

Originally Posted by 1ATony

Also make sure the two wires from the defrost grid are connected to the tabs on your hatch struts.

It's probably the switch,but I'd check everything.

Yeah, I have that problem too. The one on the driver side comes off all the time now, I'm used to always reattaching it.

But that doesn't seem to affect the switch light going on or off, it behaves the same way, just of course it doesn't defrost when the tab is off.

lexz28o · 01-15-2011, 03:11 AM

mine are connected and the switch seams to work fine i tested to see if electricity come's to the wire in the back and it dose left side lights up and right side a Lil blink?? and the grid is not interrupted anywhere.
what you guys think it is??

NINÅ · 01-17-2011, 10:34 AM

Quote:

Originally Posted by lexz28o

mine are connected and the switch seams to work fine i tested to see if electricity come's to the wire in the back and it dose left side lights up and right side a Lil blink?? and the grid is not interrupted anywhere.
what you guys think it is??

Hmmmmmmm……. we believe you are trying to say your defroster is not working properly, you’re getting power on the left side, however you’re not sure about the right.

The 12 volts enters the grid on the left, travels thru the grid towards the right.

Therefore when you take measurements you should see 0 volts on the right.

If you see voltage on the right, most likely there is an open circuit between that part of the grid and the wire to the strut which grounds it, or the strut is not making good contact to it’s mounting area.

It is possible to have a break in the grid to small to conveniently see.

You can verify with a test light.

Using the test light (the type for testing for voltage, not a continuity tester) touch various places on the grid (sometimes a needle probe must be used) from left to right, when the defog switch is ON.

On the left traces of the grid you should see full brightness on the test light, and as you move the probe to the right the illumination should dim.

If no dimming is noted there is a break on that part of the grid.

◙◙◙◙◙◙◙◙◙◙◙◙◙◙◙
Happy Racing!
◙◙◙◙◙◙◙◙◙◙◙◙◙◙◙

How Come Some Drivers On The Street Don’t Know How To Make A Turn In One Direction Without Starting By Turning A Foot In The Opposite Direction?

.