[Bob Lincoln]

Thanks, that's a great help!

Again, it only fails in elevated humidity (and it doesn't have to be swampy, just damp air), and when it fails, both sides fail to cancel. And it hasn't happened for months, but even more rarely, the signal failed to actuate in both directions (and also failed to mechanically cancel when that happened). So it doesn't appear to be a mechanical failure, but an electrical one. I'll be checking all of the solder joints in the pod connectors and the circuit board to the turn signal switch, as well as all contacts.

I should mention that this car does something I've never experienced before: Anytime the ambient temperature is below about 45F, turning the wheel even slightly in either direction results in a horrible groaning sound, coming from directly behind the steering wheel itself, inside the collar that contains the ignition switch. It sounds like a door hinge in a haunted house, or an oar in an oarlock, and it's so loud, it probably can be heard outside the vehicle. Once the cabin temperature exceeds about 45F, it does not occur, ever. It's definitely in the column, just in front of the instrument pod, and not in another part of the steering downstream. I feel the vibration/binding, but no real extra steering effort.

I have a spare steering column from my 1992, and I've been waiting for a summer weekend when I can swap it out. The '92 column has cruise control, and I have everything swapped over for cruise control into the '93 except for the switches on the steering wheel. The reason I didn't do the swap yet is that I have to swap ignition cylinders, so that the car will be keyed the same, all off the same key. I expect this problem will go away, as it never happened with the '92.

 

[Bob Lincoln]

The column from my '92 worked fine, so that will get rid of the groaning. If the cancellation is due to the column end of things, it will fix that, too. I gave my spare pod to another Allpar member a couple of years ago, so I can't replace that. However, since the condition is so sensitive to humidity, my suspicion is that there is residual solder flux on the circuit board or wire connections at the turn signal switch, that is shorting it out as the conductivity changes. I've dealt with that failure mechanism before at work. The fact that it exactly tracks higher humidity supports that theory. Will be removing it to clean it when the weather improves.

 

[Bob Lincoln]

It was NOT the switch. Could have happened in any car.

I pulled the pod, took the integral circuit board off the switch, cleaned out a lot of tin oxide tarnish on the board that the contacts wipe against, and some flux. Put it all back in the car - no turn signals, and on high beam, NO headlights at all. No optical horn.

Fuses were all good. So I brought the pod back inside and started tapping out the signals. That's when I found the root cause of the trouble.

The short wiring harness from the switch goes to a circuit board that mounds in the pod, and in turn connects to the larger left side circuit board that has the headlight switches and panel bulbs. That small circuit board has an 8-pin header connector soldered to it - or should I say, not soldered? As I tapped out the signals with my multimeter with audible continuity beep on, it was intermittent. I was able to rock the connector at least 20 degrees in each direction and break contact with the turn signal switch.

Brought it downstairs to where I have a new workstation at my bench, reflowed all 8 joints (the cracks were all plainly visible) and tested it electrically. Solid.

Put it back in the car, ALL works. Time will tell, but I predict that I will have no more trouble at all with any function in this switch. Since no mechanical stress is placed on this connector other than road vibration, I'm going to state that they were cold solder joints from the factory that all cracked over time. No other connections on that small board were bad.

So if you have similar trouble with the pod, take the switch out and try rocking connector CN2 on the small circuit board. Check its solder joints visually. This defect can kill any and all functions from that switch.

White 8-pin connector: