Killing Power Window Switches? (1 Viewer)

[Splitface2811]

When I bought my 80 a few months ago, the front passenger windows went down a bit, then up then stopped. I though it might have just been jammed, so I went through the process of diagnosing and trying to fix the issue. In the end, I found that the switch had failed and I ordered a replacement.

I wasn't too shocked about that. Its a 25 year old moving part. Things fail.

Problem is, I've just had the same thing happen again with the new switch. I don't know if I just happened to get a bad replacement, or if there's some weird electrical thing going on thats killing my switches on that door. I'm don't know much about electrics, so I thought I'd ask here before buying another switch and hoping it doesn't happen again.

Does anyone have any ideas for things that I could check to see if there's a problem or if its just bad luck?

Cheers.

 

[MurderBird45]

Did you use a voltmeter to test it and make sure it’s definitely the switch? Might be a matter of replacing the window run channel which is known to get so crusty that the friction is too much for the window motor.

 

[Splitface2811]

Did you use a voltmeter to test it and make sure it’s definitely the switch? Might be a matter of replacing the window run channel which is known to get so crusty that the friction is too much for the window motor.

I didn't use a voltmeter when I was testing it, I didn't have one on hand.

I ended up using some jumper wires to power the motor and it moved up and down just fine, so I tried a switch from one of the other windows.

When it failed the second time, I also tested with another switch and it worked fine as well. I haven't left one of the other switches connected in case there was something damaging those switches.

 

[MurderBird45]

I didn't use a voltmeter when I was testing it, I didn't have one on hand.

I ended up using some jumper wires to power the motor and it moved up and down just fine, so I tried a switch from one of the other windows.

When it failed the second time, I also tested with another switch and it worked fine as well. I haven't left one of the other switches connected in case there was something damaging those switches.

Smart. Sorry for forcing you to write out your troubleshooting. When you say the switch failed- did you replace just the rocker switch or the whole assembly that fits into the arm rest? Might be your connecting wires if the other switch assemblies in the car are able to operate the motor. I am no electrician or expert either. Just a dude drinking his coffee and handing out unsolicited advice on the internet!

 

[jellis]

You definitely NEED a voltmeter to properly diagnose this system, and the EWD. I bought a crappy aftermarket switch on Amazon and it caused hours of headache because the new switch at that window would work but not the master....."Wait what is my master bad?!?!?" I took apart the harness connectors and verified resistance and voltage at the correct pins, everything checked out OK....."Wait how is this possible that nothing is wrong?!?!?" It turns out that the design of the switches is such that if the switch at the window has too high an internal resistance (still has "continuity" but a much-more-than-zero resistance) then it can cause the master switch to not work. A bit of a tricky system to troubleshoot.

 

[Splitface2811]

Smart. Sorry for forcing you to write out your troubleshooting. When you say the switch failed- did you replace just the rocker switch or the whole assembly that fits into the arm rest? Might be your connecting wires if the other switch assemblies in the car are able to operate the motor. I am no electrician or expert either. Just a dude drinking his coffee and handing out unsolicited advice on the internet!

I just replaced the rocker switch. Could be something in the wiring from the switch to the motor. Maybe a wire has rubbed through and is shorting out. I'll have to check that.

The other switches I tried were just the rocker switches, not any of the connecting wires. Could be that the position I held them in wasn't causing a problem if it's the connecting wires.

 

[landcrshr]

A bit of a tricky system to troubleshoot.

Sometimes the trickiest part can be deciphering the EWD.

Once you filter out the minutia, the circuit simplifies to this:

 

[Splitface2811]

Sometimes the trickiest part can be deciphering the EWD.

Once you filter out the minutia, the circuit simplifies to this:

View attachment 3006370

I managed to mostly work that out. The switch just connects one side of the motor to 12v and the other to ground. Didn't know that it was grounded through the master switch, but I knew they had to both be connected for either to work.

The fault lies somewhere in the circuit after the master switch, because it doesn't work either, going up or down. Either the switch itself is at fault or there's a bad connection somewhere.