Instrument Light Problems

[z3beemer]

More info:  Disregard the earlier comment about no power to the flasher.  The attached chart PDF file) is the latest readings.  Again thanks:

240z elecr,.pdf

[SteveJ]

So the main power is hooked up right. Your chart shows that isn't a problem. And the green/blue wire has 12VDC on the 9 pin connector. That is perfect.

You said you found one cross connect in the center stack.

When you turn the combo switch to turn on the running lights now, the gauge lights should come on. Does that happen after you corrected the one cross connect? If not, with the switch in the position to turn on the parking lights, check voltage to ground on the green/blue and green/white wires where they are soldered to the switch.

If the gauge lights still only come on with the key in ON, pull the ignition fuse and see if the lights are still on. If so, repeat for the AC fuse and wiper fuse.

[z3beemer]

Latest finding on your above recommended checks.  Just to clarify: Once I corrected the cross connection in the center stack, I no longer had any instrument lights that worked.  Making the checks above , here's what I found.  I checked power at the switch solder joints under three conditions: Key on Parking light switch on, Key off parking light switch on, Key off parking light switch off.  All resulted in the same results;  No power on green/blue solder joint; 12V power to the green/white solder joint.  Next I picked up a 12V power source and jumpered it to the green/white solder joint. I now had: instrument lights, tail lights, marker lights and brake warning light on the dash.  I'm beginning to think the multifunction switch is bad.  On a related note:  when I had the wires misconnected and was back feeding thru the instrument lights, the windshield wiper motor worked.  Today when I got the lights working the wiper motor did not function (yes the fuse is good) however the wiper switch was very hard to operated I heard something click inside the switch like something broke, the switch operated easily after that but did not operate the wiper motor.  Your thoughts???  As usual ...thanks for sharing your expertise.

[SteveJ]

You nailed it. It could be a dirty contacts, or the nubbin in the switch has worn down/melted.

@jfa.series1 has some good pics in this thread: 

 

Here's a thread where we got carried away talking about the nubbins:

 

[z3beemer]

Well I ordered a reconditioned headlight switch ($$).  I'll let you know how it goes once I get it installed.  By applying power to the green/blue solder joint all the lights appear to function (except the turn signals).  Maybe the replacement headlight switch will correct that.  First things first.  I'll keep you posted.  Thanks!

[z3beemer]

Well, it was a hell of a fight but thanks to all you guys it's fixed.  Here are the details, in case someone else has the same problem.  I installed the reconditioned headlight switch, crossed my fingers and turned the switch.  Success! I had all my lights working except my front turn singles. Rear were OK.  Started fooling with the turn signal switch and got the right side working but not the left.  Squirted some contact cleaner in the switch followed up with some dielectric grease. Worked the turn signal arm.  Now I had left side working but not the right.  Started thinking that switch was bad as well.  Decided to take it apart and see if there was something I could fix.  Figured I had nothing to lose if I had to replace it anyway. Removed it and took it over to the bench to work on. Upon closer examination, I noticed a broken solder joint on the switch.  Not the wire, the solder actually broke.  I cleaned it up with solvent and resoldered it.  All lights and turn signals now work. Hard to believe it broke after 49 years of service.  I surmised the intermittent function of the turn signals was caused by the solder joint intermittently making contact. I wanted to do one move test before calling it a total success.  Test the headlight high and low beams with the actual headlights, not just voltage reading.  I connected the pigtails and took one of my brand-new headlights out of the box and connected it to the right side. Nothing. Moved it over to the left side, nothing.  As a long shot I thought maybe they both needed connected (didn't think so but I was grasping at straws).  Got the other new headlight and connected it. Now both were connected.  One worked one didn't.  Switched them around and the problem moved.  Took the inoperative light over to the bench and hooked it up to a battery, nothing. Confirming the brand-new headlight was operative.  In over 50 years of working on cars, some of those years as a mechanic, I never had a bad headlight out of the box.  So that light saga is over.  I want to thank you guys for all your help and perseverance in helping me get this resolved.  I couldn't have done it without you help.   That's why I'm a subscribing member,

[SteveJ]

Thanks for following up to share your solution. Many diagnostics I have offered people were based upon hearing how others solved their own problems.