Hello,

I've been trying to diagnose why the hand brake switch does not trigger my flashing warning light in the panel on my 1972 1.7L 914. Based on my debugging the trouble seems to be with the diode that is between the flasher lights in the panel, and the switch at the hand brake. (Left diode #41 on the attached diagram.)

But for the life of me I cannot figure out where this diode is physically located. I took out the cluster gauge, and looked at the big clump of wires, and all I can see is the other diode, on the right in the diagram, that goes from the voltage indicator to the warning lights. That is there, and works fine. But where is the other one?

Thanks,
Andrei.

P.S. The hand brake switch is #34 in this diagram. The brake fluid warning light is #32. Note that my car is an early 1972 model, and I don't have the seat belt warning light. The reason I think the trouble is with the diode is because the resistance between the warning light connectors and the handbrake switch cable is about 250kOhms both ways. I thought the right thing was for the resistance to be very low one way.

On my ‘73 it was right behind the gauge.

Well, I've come to believe that maybe that diode does not exist. It is not behind the gauges. My guess is that because my car was an early model 1972 (manufactured Dec. 1971), which still had the non-retractable seat belts and no seat belt waning, it had no diode. Here is the 1971 circuit diagram.

My main question now is what could make the wire have such a high resistance, in the upper 200k range. It is obviously not disconnected (since the resistance is not infinity). Where would you look for corrosion?

Thanks.

When I ran into a problem of my emergency brake light not working properly I decided to replace the wire from the gauge cluster to the switch. Took the steering wheel off to get to the gauge cluster easier. Took the drivers seat out, the back panel behind the drivers seat and the carpet off over the center console on the floor. All was needed to run a new wire. After all that and just before I started to run a new wire I tested once again. Sometimes the ground worked for the switch and sometimes it didn't. After looking at the emergency brake switch closely, I noticed it was loosing it's contact when I put it back into place. I forget exactly but I think I bent the switch a little bit to make better contact and placed it back into it's hole. It has worked great ever since. If all else fails, the wire from switch to gauge can be replaced but hopefully it is just at the switch. My brake reservoir switch had an issue also that was giving me fits but it was just a faulty ground and an easy fix (did not have to replace the switch). Those two wires come together and the combination of two issues made it very difficult to troubleshoot. Hope this helps.

Fuel / Brake light gauge. Right side. Next to the 41 on last schematic.
Look for a union in the brown white / blue. Its been a couple years ago but had to track it down on Matt's barn find.