RiskyBusiness82

First off I'm obliged to say thank you to the many members who've spent hours posting countless useful threads,step by step picture tutorials, and Rennslist for allowing non-registered searching through threads. Haven't had to post/make an account for over five years.

Right to it. My82 for the past few months had seemingly random issues with the headlights going up,down,up,down(at least the HL Motor is non-interference.) I could not find a tech bulletin and luckily one similar thread on this issue.

Knowns/Prior Testing
1. HL Motor good and cleaned up
2. Will only stay running with the headlight in the parking light position
3. HL's will work if i turn on ignition to pos. 3(fuel pump), and play with the HL Switch till it reaches its full stop or car will die.
4. Once signal cluster was installed, intermittent wipers behave similarly to the HL.
5. I have switched out the relay(XX) 928 618 107 00 with like kinds and some others as well.
First I believed it was my ignition possibly having too much play(dremeled every tumbler even backsides years ago rekeying.) I have since rekeyed my ignition core with new pin & tumbler set, as well as the ignition switch. Not a complete waste of time at all, but did not solve said issues. HINT: Even with great key spring return I can still hear the armature/solenoid in the relay make/contact clicking sound if I am in pos 3 (fuel pump,) and subtly go between Pos. 2(accessories). Relay has been taking apart and all contacts are on point I just don't know how to test these so called "flyback" diodes that help reduce rF and can voltage go both ways which is a little contradictory when you think of a diode, generally. Any help/feedback would be greatly appreciated as I could take any advice or wild idea right now.

Q. How do I test a forward biased flyback diode to see if it's functioning properly as a "snubber circuit" and what voltage. Is it possible to add an in-line diode after the circuit to avoid messing with all the soldering/connection points?

Goodnight from Cali, hope to hear some suggestions

ROG100

Have you replaced the ignition switch - you say you rekeyed it but that is not possible.
Did you replace the relay with another exact same relay - either 928 618 107 00 or 928 618 107 02 or 928 107 05?? Using similar looking relays does not work!!!

RiskyBusiness82

Yes ignition switch has been replaced. Doesn't really matter but I did rekey the ignition lock core with new tumblers for a better fit hoping that would solve the issue. Definitely being careful changing them out and currently has been running with the 928 618 107 02 but still same issue. The wiring diagram is one diode different as well

Randy V

How about an introduction, including pics of your car?

RiskyBusiness82

Thank you for the prompt reply Rog.

Yes the ignition switch has been replaced, and what I meant earlier is I also rekeyed the ignition core with new tumblers because it was so loose/modified/abused with dremel; that you could pull the key out while running. Have been very cognitive of the relays as we make makes going to 88. Currently Relay XX has 928 618 107 02 but still the same symptoms. Have not tried 05 yet, only difference is that it has a diode to the heat sink. I'm considering cleaning up the contacts, which do work when applied with voltage momentarily. Pops doesn't think cleaning up the contacts will work, and his point is hard to beat since we have put in over 3 relays. I'm not too good with this HL double relay especially. Just hoping for a miraculous fix here because my Dad and I are clueless.
56b seems to be a common denominator since both wipers and headlights go off together.
Cheers

Kiln_Red

Sounds like a short to me. Check your headlight plug and trace terminal 30 for compromised insulation. This circuit is hot at all times. You'll want to disconnect the battery if you need to pull the lead from the back of the plug. This wire runs all the way to A2 of your CE board.

RiskyBusiness82

Morning fellow Rennslister's, my names Greg thanks for reaching out ROG, and thanks K,
on that terminal 30 suggestion. I have three hours till work will keep you guys posted

A little about me(moreover my whip.) Been working on this car since I was 16 for over 5 years. This is definitely one of those cars where you definitely want to do an inspection because it has become a money pit. The only things stock are the suspension, chassis, and the engine. My Dad and I have changed out 3 transmissions(always rebuilt valve body) before we got lucky with one with good brake bands(slipping issues since day 1)
Have learned the hard way not to take shortcuts on these things; like putting in bigger amp fuses just so my radio would work for a couple of days until smoke came from my headliner one day. Definitely an "I told you so moment." Rewiring the harnesses that melted together and which was not exactly enjoyable. I was set on a 5 speed conversion a few months back and I had my pre mounts for my clutch and slave as per my model, but my Dad advised against it. We pulled it from a 78 so the functionality was in question especially for a huge job like that. I had just put in the shorter torque converter for the manual, but with brittle hoses etc, we went with another auto(3 speed) He's 98 always right.
After 5 years, electrically everything is coming together but I am prepared for unexpected elec. problems. These GT's really need to be maintained often given the age. Side project I'm finishing up is using Copper adhesive on some of the back 3 connectors on the pod as the contacts don't to stay in their lane. Plan is to cherry out the car in 90 days.

Not completely sure if this is the right place for an introduction but included are some pictures.
My car in my current state and some other fun/more attractive pictures

My Dad has loved these cars since '78 and now at least there is a niche that makes them affordable! We've bought and sold probably over six 928's and our driveway can be filled with 928's at times. Thanks again to the whole RL 928 community over the years. Planning on doing a newbie rekeying guide for people like me, to give back. Hope you all have a great ride today

Cheers,
Greg

SharkSkin

FWIW, filing relay contacts should only be used as a diagnostic aid. Doing so removes the hard plating that comprises the outer layer of the contact button, and exposes the softer metal underneath. This will lead to a shortened lifespan. Ideally you would replace said relay ASAP and keep the filed relay as a spare.

Somewhere down my project list is a plan to do a writeup on this problem. Somewhat higher on the list, and necessary to illustrate the writeup, is the completion of my microphotography rig(and a ton of other projects), but such is life.

Alan

Change out the X relay

Alan

RiskyBusiness82

Been busy the past few with work, but finally back at it. Just read Randy's write up right after I quickly put the pod together(flashing warning light: needs engine oil), and semi fixed an electrical pod wire disconnected by electrical tape. that had come undone (wanted a pod that went over 85mph...)
Other than that I have also changed relay X as per Alan's suggestion. This is again where it gets interesting. Now the lights are "stuck" in the up position, and work properly other than not returning back down. I have yet to check the ground wire 30 behind the CEB but about to do so(unpowered of course.) There is some definite power drain that kills my battery voltage too soon. Have checked all grounds except alternator. I know my left door pin is disconnected because if dome lights are on it won't recognize, so that can be a short right there/ if wire touches chassis. Will be checking CEB and fixing door pin, will post results.

Alan

OK - lots of things...

1) If your dome lights don't work normally - door pin switch doesn't activate them - then likely you door end lights are always on (about 4W) - this will kill a fully charged battery in a little over a week or so. Remove the interior light fuse and see if it goes away.

2) Whenever one circuit interacts with another that it should not have ANY interaction with - suspect grounding issues of some form as:

a) The most likely cause
b) The second most likely cause
and
c) The third most likely cause

e.g. don't look at ANYTHING else until you have exhausted all grounding possibilities.

Most likely here are the CE grounds, headlight grounds next to the ignition final stage modules and the pod grounds. Take them apart, clean them and make sure all expected grounds are actually connected there (count them from the wiring diagrams), make sure none are broken on the way...

3) You mention fiddling with the headlight switch to get what you want - you should never need to do anything but turn it to position 2... what exactly are these symptoms?

4) Now that you have a problem with the headlight operation - that suggests either a similar grounding issue or a problem with the HL Relay/HL motor. I'd ignore this till you figure out the grounding/running issue - it may go away on its own.

Alan

SharkSkin

I'd say disconnect the battery and drop the CE panel. You shouldn't have to disconnect anything to get a look at the backside. If it looks like anything has been burnt or spliced, pull it and repair it. The early wiring diagrams are very clear as to what connects where, so it should be easy to correct any hacking. Later wiring diagrams are a bit more work to read.