Lost turn signals installing speedo and tach

[jlynch1960]

Picked up a spare tach and speedo on the board here and installed them this morning to check their operation. '84 Carrera.

Speedo is a little unusual - 930 641 508 00 - the '86 parts catalog says it's the UK/Aus unit - marked in both MPH and KPH, but it has all the same tabs for connections.

Installed them and everything worked fine for ten miles. Then the turn signals and hazard crapped out. I swapped back to the original units to see if that might solve the problem - no luck.

Did I fry the turn signal relay? Is there a way to test it with a multimeter?

I'd like to think it's a dodgy ground on the turn signal indicators in the speedo, but would that cause the turn signals themselves to fail or just the indicators? Can't quite work thru it based on the Bentley diagram, but the existence of a relay suggests to me that the turn signals should operate independently of the signal indicators. Just to be sure, I also took apart the steering column housing and did the "Won" fix on the headlight high beam flash but that's working fine. However, the blue high beam indicator in the speedo does not light up - again suggesting a bad ground

Also, with ignition off, leaving the turn signal switch in the left or right position illuminates that side's blinker and running light so the fuses and turn signals are fine.

Going back out to tinker, but any thoughts would be appreciated.

Thanks, Jim

[bkreigsr]

Check both the multi-prong female connectors under the dash - they might have been dis-lodged during the procedure. - one is for the ignition switch, one is for the wipers - but who knows? could be related.
They plug into a relay in the front trunk from the bottom of the dash. (hand wrapped black elec. tape (4, 5 or 6 connectors.) very hard to see - you might need a mirrror to make sure they are fully seated.
If they are both fully seated, check the inline fuse for the turn signal/high beam switch under the dash.
While you're under there, check the wires on the flasher, then go over to the light switch and verify everything looks okay.
Have you checked the fuses on the front fuse panel?
Bill K

[jlynch1960]

Ran several jumper grounds from the back of the speedo to no effect. Bentley diagram had the indicator grounds as brown but they are in fact blue/white.

Hunted down the relay and it was looking kind of melted. When I plugged it back in as a place holder (it's really tucked back in there), I got my blinkers back for about 20 seconds and then they died again.

So I just ordered a relay.

[dshepp806]

what, in the world, do you mean by "looking kinda' melted"? Pics?

Doyle

[jlynch1960]

Just like I said - it was looking kind of melted. Deformed with a big plastic bubble coming out of one side of it.

Spent some time looking at the turn signal relays here on Pelican. The newer one - '85-'9_? ($7.75) has only three prongs on the bottom. The earlier one __-'84 ($57.00) has four prongs.

Has anyone used a post 84 tach in an earlier car and simply used the later relay? I will do some more searching tonight, but I haven't come across anything that noted this problem. Most posts are about the difference between mechanical and electronic units. I was operating under the obviously mistaken assumption that the electrical ones were generally interchangeable between years.

Edit - I'm starting to confuse myself. Looked up the part number on the tach and it's the same for '84-89. So why a different signal relay?

[86 911 Targa]

Originally Posted by 86 911 Targa

Here's the wiring as per my factory manual for the '86 which should be the same as your '84.



Good luck,

pm me as needed

Also, here's a pic of the speedometer connections:



I think you fried your turn/hazard relay.