Major electrical problems

[radosc]

Hi, don't know where to start looking for a failure.

Car was standing for 16 years, now it's time to sort it out.

I have almost no electricyty.

Working:
- radio
- number plate lights
- front lights
- after replacing fuses rear lights
- one side marker while in hazard lights mode

Problems:

- no start (starter motor defective)
- no interior lights / dash lights
- no windscreen wipers, horn, turn indicators, gear selector lights, heater motor, ac.
- no rear windows, no sound or nothing while trying.

Am I missing on ground somewhere or should I track every problem on it's own? Anyone had experience with similar major failure? Like for e24 there are some fixes if certain things stop working in the same time.
Thanks
Radek

 

[Orangener]

Problems: windscreen wipers, horn, turn indicators, heater motor, ac.

After 16years most probable :

windscreen wipers motor rusted
horn rusted too
turn indicators relay rusted
heater motor rusted

demount, cleanup, controll it with direct connection to 12 V

 

[jhjacobs]

Orangener is probably right about rust and corrosion. The systems you mention are generally unrelated and there is no single ground issue that could cause this. You might want to consider buying a color wiring diagram (I find mind very useful);

http://www.colorwiringdiagrams.com/bmwcars.htm

If you send my a PM with an email address I can send you a PDF wireless diagram (black and white).

- no start (starter motor defective) - Rust. Powered by solenoid (relay) which is powered directly from ignition switch. If it is automatic there is an interlock relay that required the shifter to be in "Park"

- no interior lights / dash lights - These power directly from the battery but the current daisy-chains through the horn relay and the high beam relay. Do the high beams work?

- no windscreen wipers, horn, turn indicators, gear selector lights, heater motor, ac. - The horn is a simple circuit. You may not hear the horn if rusted but you should hear the relay click if the hood is open. The wipers have many problem sources but rust is most likely. The wipers and dash / gear slect lights do share a common ground; I can't tell you where to find it though. The turn signals are also complex; they run through the light switch (power), the turn signal swith (direction), the hazard with (common) and the turn signal flash timer relay.

- no rear windows, no sound or nothing while trying. - These are powered via the load shed relay which receives power directly from the battery but it is enabled via fuse 6 and then power goes goes to the switches via fuse 9. Since you hear no clicking / sound when trying the windows rusty motors is likely but I would also have a quick look at (hit a few times with the butt of a screwdriver) the load shed relay mounted just below the fuse box - it may be sticking.

 

[Honolulu]

there's a simpler possiblility

After that time (especially if in any dampness) the prongs holding the fuses, and the fuses themselves, are probably so corroded that even though they look okay, they aren't conducting any smoke.

Disconnect battery, remove fuses. Clean fuse holder prongs, and fuses themselves, with wire brush or what-have-you.

Simple, quick, almost undoubtedly needs doing, even if it doesn't solve the actual problem. Then, after you read and get the general idea of current flow from the wiring diagram you have to get, trace the flow of current in each circuit, one at a time. Clean connections as you go with Tweek, CRC or your preferred electrical contact cleaner, plus some sandpaper or wire brushing.

 

[HB Chris]

Wiring Diagram

I see that Prospero's site says his diagrams are two pages with original color codes. When I bought mine a year or two ago it was a single page with colors that do not match the original and with little or no terminal numbers (I think). Has anyone bought one recently? They are somewhat helpful but I keep going back to the Blue Book diagrams, enlarged in pieces. I also don't think he had 3 versions of the e9 which he now does. Comments? Thanks.

 

[jhjacobs]

I bought the 71/72 diagram and it is a single page but in 11x17 format, nicely laminated. There is a modest attempt to represent the colors correctly but it is not reliable other than Brown and Red. I also ave a PDF black and white wiring diagram (two 8.5"x11 pages) that I also use. I find that between the two I can either figure things out or get completely confused. They are both missing many important details and they are different.