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Random electrical issues and I am lost!

3K views 8 replies 4 participants last post by  Billwill 
#1 · (Edited)
Hello,
1984 318i
manual
u.s spec
I am new to this whole thing to start. I have a 1984 318i that Ive been seem to having electrical problems with, and dont know what to do with myself because of it... Especially because electrical is the last field I specify in. :dunno: Anyways, I bought my 318i just recently, knowing the odometer and speedometer didnt work, and the front right highbeam was out, That was it. After about an hour of testdriving and trying everything out, I decided it was a good car to buy. Everything other than the things listed above worked, and worked great! I drove it home, and parked it that night, with everything working great. Next morning I went to start it up, and it started great and everyting like it should. Defrosted the winshield being 15 degrees out, went to leave and turned the lights on and no dash lights worked, and the rear right running light was out. All brake lights and headlights worked fine though. The problem is very intermittent, sometimes everything works, sometimes not. It seems sometimes if I mess with the fuzebox that all of the lights come on and work? Sometimes not. Then, one night, after driving it all day, i went to start the car and it wouldnt turn over. I turned the fan on, and it was very low, so I concluded dead battery. I put the battery on the charger and it went straight to green, and after about 40 minutes put it back in the car, started it, and pulled the headlights and it died. And wouldnt turn over again like the first time. Again, I put the battery on the charger fir about 2 hours this time, put it in the car. Started right up, and let it warm up for a bit not using anything but the heater. After about 10 minutes of idling, I pulled the headlight switch, and it seemed to draw alot of power, and drop the idle down about 150-200 rpms. Yesterday, I put a new battery in because I had it tested at autozone and it was bad. And it seemed to do the trick, so I thought. I drove it all around, parking it, turning lights, not headlights, parking lights, on and off and it was fine! After driving through another parking lot, it randomly died. And it wouldnt turn over, but battery was fine? After trying a few times, and wating a couple of minutes, it started right up. I drove it straight home and parked it. After about 1 hour, I came back out, it was really dark, so use of headlights was needed, and started it up. I had it idling, and it randomly died again. I started it back up and drove it. As I was driving, everything electrical would shut off and the car would want to die. Id reach over quickly and shut the fan off and it would come back to life. I turned around and came back home, it happend about 2 more times. I was done driving it that night, (last night). This morning I went and started it, and it was surging and idling like crap, and the battery light was on. after a few minutes it began to run fine, so I turned the heater on to defrost it, and left. I pulled the headlights and had headlights, but no dash lights again, and the back right running light was out. I think the side markers on the right side were out too. I left the lights off, had my stereo and heater cranked, and it drove great. I left school and came back home w/o dash lights but car was still fine. Brought it in the garage and cleaned some grounds and battery connections, and same problem is still occuring, no dash lights. This is beginning to be very stressful for me, considering it is my new daily driver. :mad: Any help is highly appreciated. Sorry for writing a book. Lol.
Thanks,
Zack:
 
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#2 · (Edited)
You need to get yourself a Multimeter...if you do not already have one!
Buy a cheap Digital Multimeter....no need for an expensive super-accurate one.

Then with the meter set to DC Volts, place it across the battery terminals.
With ignition OFF the meter should read about 12.5 volts.
If the voltage drops to about 9 volts while cranking then the battery is bad.
The voltage should go up to around 13.5 volts while the engine is running.

Check that the negative battery lead that goes onto the chassis is clean and tight at both ends. There is also a grounding strap that grounds the engine to the chassis....check that this is clean and tight on both ends.

Check that all fuses are OK and the cluster lights get dimmed by rotating the main light switch...at least on Europe/SA models....check that this knob is not rotated all the way to the left.

Check these items and then get back to us here on the Forum!;)
 
#4 ·
Checked the battery and it is new and good and met your requirements posted above with the multimeter. Cleaned and resurfaced grounds you said to check. All fuses are good too. By dash lights, I meant cluster lights too. I did all of this, and got no results, and left the lights on as I stepped outside of the garage to pull my hair out, turned around and everything was working. I thought to myself, "awesome, fixed!" I turned the lights off and went inside. Came back out to go to the store, and started the car, and pulled the lights, and they didnt work AGAIN. And now, my windows dont roll down or anything ( they did before).
 
#6 ·
For the headlight issue...try swap over the high beam/low beam relays K3 and K4 I think...I do not have 1984 circuit diagrams.

Otherwise add a seperate ground from a clean chassis/engine point to the headlight bulb ground points.

Flip over the fuse box and see if there are any loose/burnt wires.

You may have to replace the Light Switch.

For your electric windows...check the fuses and the circuit breaker for the windows.
Do you have relay K5 or K7 fitted or both? If only K5 then remove the relay and jumper pins 30 and 87 in the relay socket....see if windows now work.

This is going to be fun!!
 
#7 · (Edited)
The G200 ground located under the dash on the left side is connected to all the components in question and is likely your problem .If you remove the lower covers below the steering wheel it's back near the top of the brake pedal arm.It's a whole bunch of brown wires coming together. There's also a G201 on the steering column, but I don't think it's the issue ,though it wouldn't hunt to give it a good cleaning as well.The other one you really need to check G104 is on the left fender (inside the hood)behind the headlights ,once again look for a bunch of brown wires coming together.
 
#8 ·
I did all of these things you said. All grounds you said are now cleaned and tight. It didnt seem to change anything. As I was under the dash I was looking arounnd and inspecting plugs and connections. I pulled the harness for the lights from the switch itself, and looked at it and it seemed to have one fried connecter, and was corroded on the back. I am trying to find a new one, but just unplugging it and plugging it back in seemed to fix the problem! I mean, I cant jump to that conclusion completely just because it has been so random. But I cleaned all of the grounds and inspected the fuse box, then tried the lights and all dash and cluster lights were out including the back right tail light. THEN, I checked the light harness, and put it back on, then pulled the lights and everything worked. So it seems to be the reason I was having the problems. I havent ran into anything yet after driving all day yesterday and today strictly messing with the lights. Thanks for all of your help and ill let you know if I run into anything else. This forum is awesome! Thanks again! :)

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