Rear window defogger switch not working... Acura Integra '91

The rear window defogger switch on my 91 Acura Integra does not remain
depressed. (and the rear window defogger doesn't work)
I thought it was a problem with the switch and tried replacing it. But
I see the same problem even after replacing the switch.

I've checked the fuses and the relay and they seem fine. How should I
proceed further to troubleshoot? I'm guessing that there is no power
to the heating elements in the rear window since the switch does not
remain on at all. What gives with the switch?

Also, noticed that with no power connected, the defogger switch does
not remain depressed in the ON position. Is that normal behavior? The
other switches on the panel do remain depressed even if there is no
power.

 

Also, noticed that with no power connected, the defogger switch does

Often times the switch is a momentary type, you press it like a door
bell button and get 10 - 15 minutes of defogger. Does the switch have an
indicator light? If so, does it light up?

Measure the voltage between the terminals on each side of the window.
You should see battery voltage when the defogger is on. If you do get
voltage, proceed to measure the voltage between one terminal and the
middle of one of the defogger traces on the window. You should find
voltages ranging from 0V to full battery voltage (about 6 - 7V in the
middle of the window) depending in where you measure. If you don't (i.e.
see only 0V or full battery voltage) you probably have a broken trace on
the window. Be careful while measuring so you do not scratch the traces.
They are pretty fragile.

 

Could someone point me to the location of the relay for the rear
window defogger? I'm not sure which one it is.

Thanks.

 

This probably won't help you much, but in my '94 Civic it is in the
under-hood fusebox.

 

On the '91 Integra it's behind the driver's footwell side kick panel. There
are four at the top:
Upper front - Fog light
Upper rear - Sunroof
Lower front - Power window
Lower rear - Rear defroster

There is also a defroster timer circuit in the Integrated Control Unit
behind that same fuse block. If it is defective, the switch will not stay
down. If you hold the switch down by hand and the defroster works that way,
then the timer circuit may be bad.

A wreckers should have the Integrated Control Unit.

The manual also has diagnostics procedures for the defroster components. I
can send scans of the relevant pages to you.

 

Thanks.
No, the indicator light on the switch does not light up even if I
manually keep the switch pressed.
I'll try measuring the voltage between the terminals while manually
keeping the switch pressed.

 

Thanks Tegger. I would appreciate if you could send me scans of the
relvant pages. The address is sabysathotmaildotcom.

 

(Saby) spake unto the masses in

Files sent.

Hope they help.

 

Thanks for sending across the files. They are very helpful... need to
start diagnosing.

 

The defogger switch, fuses and the relay checked out fine. Going
through the troubleshooting chart, I need to inspect two other
items... Poor ground G301 G401 and open circuit in wires. Would it be
possible to point me to the location of G301 and G401? When it refers
to the open circuit in wires, which wires need to be checked?

I know its difficult without a circuit diagram... I probably need to
get a hold of the factory manual.

 

(Saby) spake unto the masses in

Files sent to you. Check your email.

 

ive got the same problem with my defrost switch(no lighton the button) i was wondering if i could get the files (tegger) that u sent to the others....thanks..

 

Check your email.

The original poster in this thread never did report back here with his
success or failure to resolve the problem. Too bad. I suspect he had no
luck.

One thing we never did cover, I'm just realizing now, is the little
condenser that is on the ground side of the defogger grid. I wonder if the
OP's went bad and was causing his problem?

Please post any further questions or updates to this thread. I will use
private email ONLY for sending jpegs or other binaries.