Funky Turn Signal SOLVED

[IdaBimmer]

2002 base 1972.  All lights and blinkers seem to work and blinkers work fine during daytime operation.  The left front (drivers side) turn signal remains solid when the headlights are turned on. As soon as the headlights are turned off the blinker resumes.  All others that surround the car work fine with headlights on. Grounds have been checked repeatedly and should be fine.  I'm at the end of my rope regarding the left front only working when the headlights are off.  The flasher, albeit old,  continues to operate as normal but the left front simply does not blink with the headlights on. Any ideas?  Any and all input would be greatly appreciated.

[aaron7302]

I would be suspecting the flasher relay. Borrow a friend's and test if u can. The flasher is sensitive to the resistance in the circuits, as wiring connections get old, combined with the the old flashers, they get quirky. When you flick your lights on there is more draw... you could run new wiring and such, but there is a thread about adapting a modern flasher relay to the 2002 harness with some wiring tweaks...did this on a previous car I owned, cleared up the flashing nicely....although I seem to remember the cadence was a bit different....not worth sticking to original in this case, in my opinion. Hope that helps!

[IdaBimmer]

I did read about that and I'll take that into consideration (re: conversion).  Not too many of these cars here to ask a friend but I did order a new flasher this afternoon.  Spendy little buggers.  It's odd how it cancels the blinker with the headlights on but I'll give it a try. Thanks much for your reply. 

Edited March 19, 2018 by IdaBimmer
mistake in text

[dbmw2002]

Grounds, Grounds Grounds if one side works its not the flasher. Dig deeper

[Simeon]

The indicator units are grounded through the fitting screw. I added extra ground straps between the body of the lamp and the back of the lamp cut out in the fender. 

[Mike Self]

Try this:  turn on your parking lights only (not the headlilghts) and see if the left side blinker stays on continuously.  If it does, I'd suspect some cross-wiring (or a bad bulb) in the left front turn signal, since on your car the parking lights stay on with the headlights..  The front turn signals on 70 and later cars use a two filament bulb--one filament is the parking light, the other is the turn signal.  I've seen defective bulbs where there's a short between the filaments that could cause this, or perhaps the two wires feeding the two filaments are touching.  

 

And has been pointed out, the front signals/parking lights ground through the mounting screws, so a bad ground can cause funky problems.  Replace those screws with stainless steel screws; that'll help prevent future bad grounds.

 

mike 

[IdaBimmer]

Mike,  Indeed. Your instruction very much got me back on track. During the build, there were two different bulb holders (brackets) used and the wires WERE CROSSED!  The light worked but the blinker was overpowered by the crossing of the wires not to mention the wire colors were different from left to right turn lights as I took the other one apart to inspect/compare. Probably different model years and bmw changing the colors? That confused me a bit but one was "striped" on each side which clued me in.  I noticed the ground on the wrong side, swapped wires and voila!  Cheers to any and all who helped out!  I am very grateful!

Edited March 19, 2018 by IdaBimmer
spelling error

[cocarp]

Oh damn! I've been struggling with this same problem for 3 weeks.  I removed the turn signal housing, cleaned it out, used electrical cleaner to get most of the 42 years of dirt build up, took the assembly off and swirled it in water and blew it dry with my wife's hair dryer, used sand paper to rough up the contacts, bought the wrong replacement bulbs (single post), bought the correct ones (split posts). After all that, the bulb lit up but the blinker did not work. I read this thread and realized I wired the harness hot. Thanks for the assistance with the resistance!!! ?

[Mucci]

Amen to easy fixes. Had the same problem on the other side of the car and sure enough just swapping the wires fixed it.

 

Also, I don't know if the whole grounding through the mounting holes is only the early cars but the signals fully functional with the lights sitting on top of the fender of my '75.

['76mintgrün'02]

5 hours ago, Mucci said:

I don't know if the whole grounding through the mounting holes is only the early cars but the signals fully functional with the lights sitting on top of the fender of my '75.

 

My '76 gets its ground through the screw, so it is not an early/late thing.

 

Do yours still flash if you put a towel between the light and fender?

(not that I expect you to try, just curious)

 

Tom

[jackm]

I just discovered the grounding through the mounting screws issue: unscrewed, the driver side light was less bright than the passenger, but as I tried to fit the assembly in, the light would get brighter in certain positions. Still not quite right, so will try to clean up the screws and mounting holes to see if I can get better contact. The bayonet twist on the sockets is pretty awkward, and the whole contact points and screws in the wire harness were mighty old and crusty as well. 

[jimk]

Install a ground wire.  People do it every day with the instrument cluster.