Electric windows problem

J

Joep

Member
Messages
25
Reaction score
0
Location
the Hague, the Netherlands
This problem on my 75 CSi has appeared a couple of times then disappeared again. The problem is that the electric windows do not operate with contact on or motor running but they do work perfectly when I have the left hand door open (contact either on or off).

I recently had it come up again, hit a small bump and then it disappeared with the windows working again. Now the problem has returned and I am a bit puzzled. The easy fix is to short circuit the LH door opener switch but I want to get at the root of the problem.

Looking at wiring diagrams I do not even find any connection between LH door operated switch so I am guessing this set up, where you can open and close windows with door open, has been a later addition. It seems to me either a loose wire but more probable a relay issue, but which one. Does anyone of you have any suggestions where to look?
 
My windows operate with the ignition off and the door open. I was told by a member, (Chris Macha), that this is actually the way it is supposed to be. Perhaps BMW was thinking of a way to save on fuel by enabling this feature.
 
Last edited:
My '74 3.0CS has this feature as well. You have a special version of the door switch in your driver's door jamb, that not only powers the interior light, but simultaneously operates a relay under the dash to power the windows. I'm pretty sure I found it in one of the wiring diagrams in the blue books.

Don't short circuit that switch or you will have the worse problem of your battery draining from a constantly powered relay. That particular screw up by a PO took me a long time to sort out. :-(

Sounds like the relay is not getting consistently powered by the ignition switch.

Charlie
 
window relay

I think the window relay may have been inserted in the `73 models (I also thought it might be US only but apparently not). With the driver's door open, push in the door jamb switch, you should hear a relay click under the dash by the hood release. I always thought I had a short! My windows always work with the key on but as soon as I turn off the key they stop, unless I open the door. It is an anti-theft feature. The PO had jumped a wire from the cigar lighter to the shift console window switches to keep power on at all times which I removed.
 
window relay

Also check all of the connections, since hitting a bump turned them back on. There is a connector in each front kick panel that can be loose and made me think my window motor was shot. After replacing the motor I found the loose connector.
 
In my 74, there are two relays involved with the electric windows: one is operated by the driver's door switch and the other turns on with the ignition. They both have to work for the windows to operate with the doors closed. If one of them is inoperative, the windows work only when the door is open...had that problem for about a year until I figured out the wiring diagram. In my car, both relays are located next to each other in the left hand underdash compartment area.
 
I had this feature on a 77 Euro E24 and I read it as a convenience feature. Half the time one turns off the engine only to realize that the windows are not up or fully up. No problem, one can raise the windows as one opens the door, which the driver has to do in any case to get out of the car. Now I see this feature on modern cars for the radio, namely the radio stays on after shutting down the engine and until opening the door.

Back to your problem, find where the involved relay is, or drive with the door partially open...
 
Problem solved Gentlemen.

Indeed as it turns out there are 2 relays involved in operating the electric windows, for this set up. The relay which gets powered by turning the ignition was faulty. It is the second relay on the left hand side under the dash, counting from the driver in forward direction, the 3rd relay is the one activated by the door switch.

So I thank you all for your comments, not in the least the more humorous ones.
 
Electric window relays

Funny that you brought this perennial issue up.
Last night when I got into my car near Munich to drive 350 miles to my house in Switzerland, the windows started to mess about. The car is in perfect condition and I have not had this happen before, on this car. They worked off and on, but I didn´t realize that it was dependent on ignition and drivers door being open or closed.
I just thought they were moody. The car is a late 74 car, sold new in Italy.

Are you talking about the 3 relays, in a row, above the bonnet release handle, to the left?

So the second or third is faulty, and will need replacing then?

Is this specific to the later >74 cars only?
 
relays

Those are the ones! Put your hand on the third relay and push in the door contact, you will feel the relay react. I just learned that the #2 relay is for the ignition power, you learn something everyday from this group.
 
Door contact

According to the White books, only the CSL ?!? and all US cars had this double-contact on the A-post. Most of my cars are Italian rather than American market cars, but all have the 3 relays in a row, mounted on a common bracket. I wonder what they are used for on Euro cars?
The car it happened to yesterday was sold new in Italy, but lived many years in the US, where it was entirely restored.... What happened before the faulty windows issue, was that a double cigarrette pack sized stereo component fell down on top of the relays. It is supposed to be stuck to the body above with 2-sided self adhesive, but came down and is relatively heavy for its size. That might have caused the problem.
I will now investigate, and check with W&N if they have these relays in stock.
 
No real need to contact W&N, just go to any shop with car supplies and you can get the relay there. Just be sure that it has the right "format" or placement of the 4 pins (which you can check by looking at the relay and noting where the numbers 30-85-86 and 87 are located). By the way, relays 2 (ignition) and 3 (door operated) are the same so you can check whether the relay is the culprit. Good luck.
 
Recently the windows stopped working altoghether in my 74 CSi, sold new in Italy.
It has the double wire door contacts.
Yesterday I found the grounding of the contact to be poor. I found this out by keeping the interior light at far left (normal position) and pushing the removed contact (with wires attached) against the lower A-post.

The windows started working and I was pleased.

Today, I notice that they only work with the driver´s door open. Not very satisfactory.
A relay issue or what might have happened. Only relay 2 and 3 relate to this I understand.

All ideas welcome.....
 
Thanks to very knowledgeable people in this thread, and a bit of fault finding, I now know that #3 relay is faulty. I replaced it with a similar relay, bought from W&N but with a 5th pin in the middle. I thought it would work, but it actually set the ignition on when I inserted the relay !!!! (into the second position). I quickly removed it.
So now I need to buy another one at a local auto electrician.

I beleive it was damaged when a sound system box, attached to the top of the compartment fell down and hit the relays.

(This reminded me of a Swedish Jaguar mechanic friend of mine, who back in the early 90s, programmed the remote lock switch on his key fob to set off the ignition (it was an automatic transmission model with start inhibitor switch). Pretty cool in one way).

Again, this board is very, very good, and I/we learn from it regularly.
 
On another ´74 car, the motor would not work, even with the (driver´s) door open.
When I pushed the button/switch, I could hear the click from the relay, so that seemed to work. I then took out the 2 cable contact in the A-post and replaced it, and that solved the problem.
 
pmansson said:
On another ´74 car, the motor would not work, even with the (driver´s) door open.
When I pushed the button/switch, I could hear the click from the relay, so that seemed to work. I then took out the 2 cable contact in the A-post and replaced it, and that solved the problem.
Click to expand...

this is similar to what just happened on my car.

the windows worked yesterday, now they don’t... just the front windows don’t work. The back ones do. door open or not. Ignition on or off. I hear the relay clicking when I push in the door contact.

could you expand on what the 2 cable contact in the A post is?

should I try replacing relay #2 & #3 first?
 
posix said:
this is similar to what just happened on my car.

the windows worked yesterday, now they don’t... just the front windows don’t work. The back ones do. door open or not. Ignition on or off. I hear the relay clicking when I push in the door contact.

could you expand on what the 2 cable contact in the A post is?

should I try replacing relay #2 & #3 first?
Click to expand...

HBChris helped me figure mine out for a ‘74:

(1) if only front or rear don’t work you have a tripped or failed circuit overload breaker (red buttons on lower dash panel by your right knee

(2) if both F/R don’t work when the door is open, check the power window load shedding relay in the driver side glove box (see pic), #3

(3) if both F/R don’t work when the door is closed and ignition fully on, check the door A-post light switch for proper grounding when door open. If that’s ok then check the OTHER power window load shedding relay in the driver side glove box (see pic), #2


C51C7080-87EA-456D-B635-6BBF8DB4C595.jpeg
 
Last edited:
bfeng said:
HBChris helped me figure mine out for a ‘74:

(1) if only front or rear don’t work you have a tripped or failed circuit overload breaker (red buttons on lower dash panel by your right knee

(2) if both F/R don’t work unless the door is open, check the power window load shedding relay in the driver side glove box (see pic), #3

(3) if both F/R don’t work when the door is closed, check the door A-post light switch for proper grounding when door open. If that’s ok then check the OTHER power window load shedding relay in the driver side glove box (see pic), #2View attachment 99742
Click to expand...


It was the circuit overload breaker! It was tripped for sure. Windows working again! Wow. Thanks for saving me the time I was going to spend trouble shooting the relays and finding loose connections!!
 
All my US 74CS electric windows work except the front right (passenger), with the ignition off. There are two wires to that window motor. I assume one for up and one for down. The down wire gets power when the window is up, the door is open, ignition is off, and the switch in the console is operated. Ditto the up wire when the switch is operated in that direction. Motor does not respond at all either direction, no motion, no noise. I assume a bad motor. Looking for instructions to remove the motor but all the stuff I found online is for manual windows, or windows with motors that do not look anything like mine. It's a flattish box with male spade connectors on the downward facing end. See photo.
 

Attachments

  • 20240813_115202.jpg
    20240813_115202.jpg
    252.7 KB · Views: 14
Last edited:
You must log in or register to reply here.
Back
Top