Window problem

[Hotmommaracing]

Bought an 89' 325i sedan/5 spd a few weeks ago. Altogether in good shape, body in excellent condition and a few niggling (is that a word?) issues I expected with a 23 yo car but nothing I didnt think I couldn't handle over time.

When I bought it, I knew the rear windows did not work but fronts did and ac was cold so I figured no big deal. Right about the time the ac stopped working (problem began only blowing on highest setting and now not blowing cold) the front windows stopped working as well. When I push any of the window buttons, the illumination in all four goes out for a few seconds, then comes back on. The windows don't move. I've checked this with the stupid window circuit breaker button both on and off - no difference. I can't imagine all four motors have crapped out but anything is possible. Any ideas?

[Kozworth]

Open the bentley and see what all four connect to. Maybe there is a bipolar ground that connects all the windows, or a fuse. I dont have my bentley next to me otherwise id check and pitch ideas.

However, I did have a circuit breaker that was funkey. It would not reset itself, and would only work if i held it down then hit a window switch. See if you got a buddy of yours to swap out the circuit breaker. Im pretty sure there is a way to test them online (i was looking into it but my friend had a spare breaker, so just traded me).

[bmwstudent]

Bipolar ground? Very interesting theory, please tell me more.

[StereoInstaller1]

You can download the ETM (Electrical Troubleshooting Manual, the actual BMW stuff) from www.wedophones.com

If the light on the switch is on, you have power, but from your description, almost sounds like a bad ground connection.

Possibly the rear door switches are in series with the front switches? If that were the case, a bad switch would kill the rear windows, but I cannot imagine there are any series connections with the front doors too.

Gl, and go find your electrical manual first.

Luke

[Hotmommaracing]

Spent some more time with this problem yesterday, studying the electrical diagrams in the Bentley manual and testing various things. When I brought power to front driver's switch from another source, both front windows opened. No such luck with the rears. Thought the problem might be the circuit breaker but I was able to rule it out.

Here's where it gets weird - when I removed the REAR window lockout switch (which appeared to get and send power when engaged) and bridged that circuit with just a wire, the FRONT windows opened. I cannot figure out how a bad rear window lockout switch was preventing the front windows from working but it was. Going to try a used one off fleabay as I couldnt find a new one for less than $75.

Still no luck on the rear windows however but I'll keep working on it

[Gregs///M]

Dimming illumination is sure sign of voltage drop for system, if all switches dim as well. Ground for window circuit is located above the brake pedal. Remove two 10MM bolts and clean connection with wire brush. Also clean contact point to chassis ground. These connections are known to corrode over 20 or so years. Also causes cluster problems.