Blinker issues (one side), checked relay, grounds, bulbs, what am I missing?
 

Good morning all!

5/9/20 UPDATE: Problem solved! Dennis (timmy2) spent over an hour with me on the phone walking me through tracing many points to ensure continuity. After everything checked out we traced the prongs on the working side and found out they were swapped on the problem side. Parking light tab and blinker tab. I was ready to take the light housing apart and swap the wires when I thought to flip the bulb. IT worked! Good signal arrow and good brightness This particular housing also is missing the euro parking light tab and wire. New from Porsche. :confused: so the bulb sort of catches it pegs on the housing and will be OK. I will fight this battle another day but its working. Thanks again Dennis.



I am hoping to catch some of the 911 electrical experts sitting in front of their computers during this unfortunate time of quarantine. Yes, I searched and consulted with friends which got me this far.

These were working at one point, I think. I am in the middle of a restomod and lost track of that detail.

The issue:
Double flashers when left signal is activated. Left front signal is noticeably dimmer than right. Front only. Left rear is normal.

What I have done so far:
1. Checked for proper battery voltage on both batteries.
2. Checked and rechecked grounds at all lights.
3. Took apart and checked the bulb contacts on the left front light, as well as wiggled the harness as the lights were blinking hoping to see a change.
4. Checked instrument cluster ground in trunk near relay.
5. Swapped relay for a similar known working one and yielded the same results, as well as ordered a supposedly new Porsche OEM (Blinkgeber) which gave me solid lights, no flash at all.
6. Desperate, I sprayed contact cleaner in the blinker stalk, then air.

What I think next steps are and please comment:
1. Finding another left front light. These are new OEM by the way.
2. Taking apart the turn signal housing/stalk and cleaning the contacts better or looking at the ground, if there is one.
3. Don't signal for left turns.

Could be a bunch of different issues from a poor connection in a wire/ connector to a faulty bulb et Make sure you check the rear if you didn’t replace those first. Get a meter and use process of elimination.

Check the resistance in the bulb contacts. Check the wiring to the bulbs. Something is wrong in the wiring, probably corroded out over time.

Check the wire at the fuse panel. Maybe loose or in their poorly.
You could do a continuity test from fuse panel wire to the lamp socket as well.

Is the fluid full? :D

I have a reoccurring issue with the right rear on mine. It's always the spring contacts. I clean the bulb and contacts and then grab the end of the contact and bend it out to create more pressure. Seems to always fix it for a while. Some day it will break.

Second the spring contact

Not sure if this will work on a '71 but it solved blinker issues on an SC:

Unplug the hazard switch from it's socket a couple of time to freshen the contacts.
I have seen this problem twice on folks' SC's in the last couple of years.
Don't forget to clean the fuse contacts.

Good Luck!

Checked and cleaned fuses, aside from the fuse being a 16A, it is what was there, I ordered some 5A. Continuity test passed. Thanks!

Replaced bulb - same result. I wish it was that easy. Thank you.

Just ran out and tried this, no luck. Thank you for the idea though.

No go. Thank you anyway.

The lights are new as are the wiring harness as the light. What should I check the resistance of the bulb contacts against? The post on the fuse panel? Thank you.

Light harness is new, bulb was swapped. Rear is good. Thank you.


Thank you again for all of your recommendations. An new interesting tidbit came to light (haha) during some of this testing. When the parking lights are active the left side front main bulb ( the light in question) which is dim when blinking, is super bright when the parking lights are on vs the 3 other lights around the car.
I know these bulbs\sockets are dual filament, could there have been a mistake when the light was made and the contacts on the light housing were flipped? Would that matter in this situation?

When I was testing continuity I just assumed the parking light fuse contact was the one to test to the light socket and passed, but was not paying attention to the top or bottom tab in the socket.

hmmm...

If I get a minute I may have to take the lens off the right light and compare.

any chance dual filament bulb is 180 degrees out? yes it is possible

I thought about that but carefully matched the pegs on the bulb to the socket and turned the right way.
Thanks!

rxtom. does the left front blink when the double flashers happens, or is it on steady?

By double flashers do you mean hazard lights? If so it does blink dimly like it does when signaling left with the car on.

Thanks!

rxtom,
here is what I want to know:
Double flashers when left signal is activated.
Does that mean the two arrows on the dash light up? Are they steady, or flashing?

AH. They are double flashing, but dim compared to what the normal brightness is when the right turn blinker is working correctly, and actually the first blink of the left turn is normal then quickly goes to double flashers. Dim.

It was fun sending you all over the car today Rob.... you were a great student. :)
I’m Happy that all your other wiring is functioning correctly and we found the wiring problem.
It is great your temporary fix of reversing the bulb will work. (For now)

Ha! You are one of the greats in the Porsche brain trust for sure. Your knowledge of the wiring and harness making is second to none. I learned a lot today in that hour!
Thanks again Dennis.

Glad you got this straightened out. Looks like you had competent help!