Occasional extremely fast left turn signal

[tomstin]

85 325E, occasionally the left turn signal blinks extremely fast to point the relay can't keep up. Much faster than the normal fast blink when a bulb is out.

Right turn signal works fine, 4 way flasher works fine. All bulbs work.

The turn signal switch is a few years old new from BMW. I've had the switch out several times and cleaned the grounds and checked all the wires. I checked the continuity of the switch. Put it back together and it works fine. Then, all of a sudden it starts the fast blink and as soon as it starts, sometimes it goes back to normal...sometimes not.

I have a new relay on the way. Any ideas?

[Dagamus(NM)]

Your new relay should fix it.

[reelizmpro]

Usually, it's just a bulb contact issue but your problem seems to be a little different. Hopefully the new relay fixes it but it's still worth cleaning up the bulb contacts as they do develop high resistance due to corrosion over the years. Wiggle the front bulb while the left turn signal is on and see if anything changes. Also check the 3 prong connector behind the signal housing as well. Goodluck.

[tomstin]

Okay boys and girls, I'm still at it. I cleaned every connector, ground and junction I could find. After a 40 minute drive around town, thought I had it fixed. Last turn into the neighborhood, it's back! Came home to the Fedex package with the new relay, installed that. First left leaving the development...and it failed again!

Took the rear taillight assemble apart. There was some corrosion on the bulb contact to the point where the multimeter would drop continuity in places on the contact. Must be it...RIGHT? Heck no, back to the quick blink or to the point where the relay can't keep up and just buzzes.

When it fails, turning on the flashers, everything works, back to turn signal, still fails. The next turn, they're fine.

I have a copy of the wiring diagrams and the only thing remaining in the turn signal circuit is the switch. I have a used one on order.