735i electrical system

[redhed]

I had a problem with my 1988 735i electrical system. Things started shutting down and sometimes the car would not start, even though the battery is fine. We thought it was the alternator. Well, turns out, it's not the alternator. Last night, the car started up fine, but all the dash displays had reverted back to German all by themselves. So we re-set it back to English. Then the interior lights wouldn't come on. So we cut the car off. Waited a bit. Cranked it up again. The interior lights came on, but the dash was all in German again and would NOT re-set back to English. We cut the car off, let it sit a bit, went to crank it back up and it would not crank. The battery had power, it was trying to turn over, but it would not. Could it be the starter? Could it be the computer? HELP!!

[KC Ron Carter]

If the OBC is being reset to Germain it is loosing power.

The alternator regulator is a very hard unit to test fully.

I would guess ether the battery is lossing a ground, or the voltage regulator is creating a direct short at random times.

Later,

[redhed]

Thanks, KC Ron. I had the alternator replaced, but that didn't fix the problem. Turns out it was simply the battery. Your post here helped me to realize that. I'm going to put an Interstate in it this weekend and that should take care of it.