Turn signals inoperable, but hazards & L/R independent parking lights work

[famoroso]

Greetings Pelicans,

I've searched "inoperable turn signals," but I haven't found this specific issue.

1986 911

Turn signals recently stopped working.
Fuse began to blow whenever turn signal was switched on.
With the ignition switched off, the turn signal switch set to right would illuminate the right side F&R parking lights AND with the signal switch set to left, it would still illuminate the right side F&R parking lights.
Hazards worked as per normal.

I know that the engine compartment light commonly shorts to ground and it is on the same circuit as the left turn signal. I checked the engine compartment light and it was , in fact, shorting to ground. I disconnected the engine compartment light at the connector in the engine bay. I also opened up the LF turn signal housing and the bulb's spring loaded electrical contact had come loose, the reflector ground wire had come loose and the upper female spade wiring connector in the housing was loose / disconnected. I remedied all of the above, including replacing the turn signal relay with an original relay of known good condition for good measure.

The turn signals were again operable. After hours of troubleshooting with test light/ DVM, cleaning up the fuse box and fuses and the above captioned repairs... I was ecstatic in my triumph.

However... When I went to shoot a "turn signal repair accomplished video" a few minutes later, the turn signals were again inoperable. This was FRUSTRATING to say the least.

Now
The turn signal stalk is functional when the ignition is off, in that it illuminates the L & R parking lights as intended and the hazard light still operates all four corners.

If I select either the L or R parking light with the ignition off, they illuminate as designed. If I then turn the ignition on, the parking lights go out, but the turn signals do not come on.

I'd love to hear what the PP collective has to share about this issue. I'm all ears.

[gsxrken]

I recently went through a very similar troubleshooting exercise and long story short it was my flasher relay. There’s something overly complicated about them in our cars, so buy the Porsche part, not the $11 aftermarket one that sometimes works. Mine seemed to test ok on the bench with 12v so it sent me into hours of chasing wires like you. Worst part is a must have damaged my AC thermostat tube in the console battle b/c my AC doesn’t turn on now, so I have to go back in for that.

[famoroso]

Female spade ground connectors had come loose and disconnected from the rear wall of the housing and the back of the reflector. I used a small pair of Knipex Pliers Wrences (parallel jaw pliers) to reshape / close up the female spades. I also used a fiberglass pen and a Dremel wire brush attachment to clean contacts, male spades, ground points, etc. I then applied Deoxit 5 to all electrical contacts prior to reconnecting wires / reinstalling the bulbs / reassembling the housing.



The hexagonal shaped metal piece holds the spring loaded bulb contact into the back of the reflector. It is swaged into place. One corner of the pot metal swage broke off in this instance and everything was loose, including the bulb contact, in the back of the housing.









Components cleaned and unit reassembled. Note the broken corner of the pot metal reflector, top left.



Added a length of Gorilla tape over the hexagonal piece.





These housings will eventually get SpokeWorks LED boards, lowering the current draw and moving heat away from the bulb socket, so the Gorilla tape should hold. However, I need to troubleshoot / sort out the turn signal issue with stock incandescent bulbs and relay first, before any modifications.

[famoroso]

Originally Posted by gsxrken

I recently went through a very similar troubleshooting exercise and long story short it was my flasher relay. There’s something overly complicated about them in our cars, so buy the Porsche part, not the $11 aftermarket one that sometimes works. Mine seemed to test ok on the bench with 12v so it sent me into hours of chasing wires like you. Worst part is a must have damaged my AC thermostat tube in the console battle b/c my AC doesn’t turn on now, so I have to go back in for that.

Thank you.

I replaced an electronic Hella unit (on the left) with an original 1987 relay (right) of known good condition (pulled from one of my cars) as part of this process. Both operate the hazards normally. I will install the flasher relay from my other 1987 and retest.



What was the console battle in relation to your turn signal troubleshooting? This car just had its AC thermostat replaced.

[famoroso]

Sorting the wiring on this car has been a challenge (countless vampire wiretaps everywhere). These before pictures of the fuse box show some of the disrepair.

I've since installed the properly rated fuses, cleaned (fiberglass pen) all contacts & fuses, re-tensioned all the contacts and applied Deoxit 5 to the whole thing. I have new ferrules en route for some of the wire ends.

*Graphic Content Warning*










WTF is this ATX fuse (removed prior to pic) & holder doing here?! Acting as a fused busbar between the two turn signal circuits??? Why? I've since removed it.

[famoroso]

Update

I've now tried all three of these turn signal relays (two original 1987 units and a Hella electronic version) in one of my 1987s and all three work (hazard and turn signals) as intended there.

So,.my issue does not appear to be turn signal relay related.



Ugh.

[917_Langheck]

Off to where you don't want to go... headlight switch and turn stalk, if for nothing else to see that those are not the issue. Given the vampire taps you mentioned who knows what circuit is now inadvertently being pulled into the loop.

[famoroso]

Originally Posted by 917_Langheck

Off to where you don't want to go... headlight switch and turn stalk, if for nothing else to see that those are not the issue. Given the vampire taps you mentioned who knows what circuit is now inadvertently being pulled into the loop.

Yeah. Hope springs eternal.

[famoroso]

Well, there were three things wrong with this car's turn signal...

1) the engine compartment light that had shorted to ground.

2) the "deconstructed" LF turn signal, and...

3) A wiring ferrule issue on the bottom of the fuse box. Noteworthy in that it wasn't at one of the 5 Amp turn signal positions though.

I'll confirm which fuse it is and report back here.

Regardless, I found the loose / intermittent connection, remedied it and I've been signaling fool in the interim.

Have turn signals, will teavel... 5:00 AM departure from SD to Park City tomorrow. More later.