electrical and ignition Wiper/E-brake connection? New alternator woes...

[Philbert]

Just installed a new 320i alternator(AL116) in my '74 and have had a series of issues since. First, full confession, I managed to short the B+ post to the alternator body and melted the red charging wire ( too embarrassing to tell how I did that...). I opened up the wiring harness and replaced the wire. No other insulation appeared to be damaged. All seemed good but then I found my gauges were jumpier than ever. I did a search and finally discovered that I was missing a chassis to ground wire. I installed that. Now I get 14.5 volts across the battery terminals and all gauges are rock steady, so I'm thinking I didn't actually damage diodes or VR inside the alternator. But then I saw that my e brake light was staying on whenever the key is in the "on" position. I checked connections and switch function at the fluid reservoir and at the handbrake lever- both seem good. Then I noticed also that my wipers are dead, though the washer pump works. Are the washer and brake light somehow connected, did I maybe fry some relay that affects both? Or do I actually have 2 separate issues? I had no problem with either system before the alternator upgrade. I'm thinking I just jiggled something loose somewhere but haven't found anything obvious. A wiring diagram would be nice but neither Haynes or the FAQ archives seem to have the correct one. I'd appreciate any suggestions about what to check next. Thanks all, .this forum is great!

[Henning]

Hi Phil,

 

unfortunately with changed fuse numbering- but a diagram:

 

 

It's the only one I have here, but will try to find a better one. The most symbols in the drawing are self-explaining.

 

Hen

 

Edited March 8, 2015 by Henning

[Philbert]

Thanks for sending the drawing. Unfortunately it's not at a high enough resolution to read. Please do let me know if you find another that's more legible. Funny that no one seems to have diagrams for the 74s...

[Mike Self]

A thought on the wiper problem...your wipers are controlled by a relay that's on a circuit board with transistors and such--up under the dashboard near the hood release handle--it's the larger of the two, marked "wisch-wash-geber" or something like that (German isn't my strong suit).  It's entirely possible you fried something on that circuit board.  

 

Remove the relay from its plug, and carefully bend the outer cover around its edges until you can pry it off the circuit board--be gentle and don't break the cover.  Visually check the circuit board for burned/fried components.  I had one fail (it was a resistor) that prevented the wipers from functioning but the washers worked OK.  

 

And of course before you do all this, make sure the fuse is good--on a 74, wipers, washer and brake lights (not the brake warning light) are on fuse 5.  

 

As for the brake warning light, are you sure the little bracket that holds the handbrake warning light switch isn't bent so that it allows the switch to be on all the time?  The bracket is pretty flimsy--an afterthought (pre '74 cars don't have this feature) and is easily bent.  

 

cheers

mike

Edited March 9, 2015 by mike

[Buckeye]

http://www.bmw2002faq.com/topic/142678-1976-wiring-diagram/

[Philbert]

Thanks for the responses. I went ahead and ordered the wiring diagram from Prospero. (How Shakespearian...) I'll check out the relay tomorrow, yes I'm sure the handbrake bracket is ok. My understanding is that either the handbrake switch or the brake fluid level switch going to ground will cause the light to turn on. What's puzzling is that they both seem ok. Am I going to ground somewhere else? And again, is there there some interconnection somewhere between the brake light circuit and the wipers? The Haynes diagram for the tii North America seems to show a shared ground (brown wire) between the wiper motor, the brake fluid level switch and the "wiper washer transmitter" which I assume is the stalk on the steering column. Are the 74s connected in some similar way and does this have something to do with my problem(s)? Hopefully, the Prospero diagram will shed some light on that...

Phil

[Mike Self]

Phil

FYI the "wiper washer transmitter" is the relay that controls those two actions...not the steering column stalk.

 

mike 

[Philbert]

Is under the dash next to the "wisch wasch" control unit? I noticed a relay there yesterday that clicks every time I move the wiper stalk to low or high speed position. Is the clicking a sign it's malfunctioning? Can anyone tell me how to test it? Electrical newbie here...

[Beaner7102]

A relay is an electromagnetic switch, give the magnet power and it opens or closes the circuit.

This is why they click when activated. It does not mean they are dead.

Sorry I dont know how to test that exact relay. Beaner7102