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1986 325es turn signal problem

6986 Views 11 Replies 4 Participants Last post by  bmwlrj

I am having a problem with turn signal on my 1986 325es.

Right turn signal function works fine with no problems.

Left turn signal:
* switch is blinking speed/sound is fast (just like if a bulb was burnt out-right side blinking is normal speed-sound).
* light on dash does not light up and neither does the front or rear exterior lights work while the blinking/switch is fast speed/sound.
* I have replaced both external bulbs and still does not light up. I switched out rear light assembly with right side and still does not work.

I only drive this car maybe 3-4 times per year in the summer only. The left turn signal for the past couple of years did work intermittenly....and now not at all.

There also may be a related issue with left side headlight light: when I turn on the brights the left side low beam does not work. Left Low beam works okay when brights are not switched on. No problem with right side.


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Sounds like the old BMW bugaboo, bad grounds. If you have a volt meter, check for voltage at the bulb holders while grounding the meter on a known good ground (bumper should be good). If you have voltage there, the light has no ground and can't complete the circuit. Same with the low beam. Check for voltage with the headlights on high beam...the low beam should have voltage at the same time. I'm guessing you need to do a "disconnect grounding points, clean and reattach" maintenance on the lighting system.
thank you very much for the reply...I can fix just about anything...EXCEPT I hate dealing with electrical...I have a voltage meter but have never used it....I will try to do as you you have simple/instruction on these step to check for dummies?
thanks again
Is it an analog meter or digital? Analog has a swinging needle, digital has numeric readout.

It should have a settings dial regardless. One of the "ranges" should be DCV or simply DC, and within that range will be (probably) a 20v setting. That means it will measure up to 20 volts DC. As long as the setting you use is above 12 volts and is for measuring direct current (DC), it will work. You use the positive (red) lead to probe the connections, with the negative (black) lead firmly attached to a GOOD ground. If it's an analog meter and you accidentally get the lead reversed, the needle will swing backwards and you won't know what the voltage reads. A digital meter will show a minus (-) sign but will still read the voltage, either forward or back. Turn the key to the run position, turn the light switch on (turn signal, headlight, whatever it is you are trying to check) with the bulb disconnected. Probe the bulb contact with the red lead, but BE CAREFUL to not short the lead to the ground or you'll blow the fuse to that circuit. If you get 12 volts showing at that contact but the bulb won't work, it's either the bulb that's bad or the ground connection for that bulb is bad.

BMWs have a gazillion ground connections. If you see a bundle of brown wires you can bet they end in ring terminal connections and they're bolted to the chassis or engine block somewhere. All it takes is for one to lose connections to create all kinds of weird lighting and/or running problems.
I think I can handle that...thanks for the nice details...I think my meter is analog..but I will check and let you know....I may not get to it until this weekend..thanks so much...have a great day!
My 85' does the same thing. My right turn signal will buzz fast but not actually light up the turn signals. But if I pull up a little more on the switch it will work. I think its actually the switch not the grounds on this one. Mine is also tied into my obc so it adds on to my costs.
my OBC is also connected with signal switch otherwise I would have purchased one and tried that first..but costly.
Try switch cleaner on the contacts in the signal switch. Contacts can oxcide over.
The contact cleaner worked...thanks BMWFatherFigure....I took of the steering wheel, column covers and turn signal switch and strayed cleaner liberally and it works perfectly easy fix...THANKS!!
well it was a partial for a day or so without it is working/not working intermittingly...I think it must be the switch...found one online for $135.00 plus shipping..
Sorry the fix didn't last. At least you are now sure where the problem is/was. Could you get at the contacts to clean them physically? I know that the factory crimps the switches together. What sort of quality do BMW think they produce? 26years of use and it fails.........................
disassembled everything again and cleaned super good and wire brushed contacts and it is working again..has been working great..just in time to put it in storage for the fall-winter....thanks for all the support.
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