Let there be light... wait where'd the light go?

[Rusty Shackleford]

So I spent last weekend replacing the dash vent cables, and all the dash bulbs. Yes, even the heater controls and clock work. I should say worked.

Last night, I took a little drive in the rain and while tooling along, all the dash lights died.

To make matters worse, I spent a day installing a keyless entry/alarm which was working perfectly, but now the central locking system doesn't seem to be getting power.

I've checked the fuses, actually I replaced all the fuses just to be sure.

There's a little bit of a leak around the windshield frame, which I'm sure got something wet.

I really dread taking the dash apart again.

Anyone have any ideas which relay powers the central locking system, or where in the flagnarp the dash illumination could fail other than the fuses.

The parking lights/headlights work.

--
1978 530i: Reseda Green & Polaris Silver, w/baby poo yellow vinyl interior, 4 speed to 265 conversion, BBS front spoiler, FoHa rear spoiler, 14X7 BBS wheels.
1978 530ia: Polaris Silver parts car, lots and lots and lots of rust.
1978 530ia: Graphite/Charcoal project "Shut the wife up"
1978 530ia: Polaris silver (rust free) project "Blow Job", TCD Turbo Kit on a Korman Prepared 3.2L, MegasquirtII, blah blah blah.
1984 633csi: Reseda Green a.k.a. project "Pig-Shark" looks like a shark handles like a pig.

[Mike W.]

The central locking all works off the drivers door unit. Dash lights work off of the headlight switch. My guess is you have a ground problem somewhere.

[alotawatts]

The headlight switch is also a rheostat for the dash lights. Check / clean the coil windings. Or maybe just a clockwise turn will light things up....thats how I fixed what I thought was a dash light problem.

[Rusty Shackleford]

The central locking all works off the drivers door unit. Dash lights work off of the headlight switch. My guess is you have a ground problem somewhere.

I'm leaning toward a grounding issue with the central lock system. Time to break out the test meter. More to the point, time to take the dang door apart yet again.

[Rusty Shackleford]

The headlight switch is also a rheostat for the dash lights. Check / clean the coil windings. Or maybe just a clockwise turn will light things up....thats how I fixed what I thought was a dash light problem.

Yeah, I tried twisting, and then sprayed a little tuner spray (electrical contact cleaner) back into the switch as best I could. No luck there.

I did discover I can tap the dash above the headlight switch and I have dash lights. It's time to pull that mess apart and find the short.

Three Cheers for Electrical Gremlins!

Hip Hip!

Eh. Whatever.

[Rusty Shackleford]

Well I'm not sure if it's one in a million, however the problem with my dash illumination turned out to be... wait for it...

The headlight switch.

From what I could tell, the switch is assembled, and then the corners are crimped to hold the thing closed. Either through heavy usage, time or poor assembly the crimps at the rear of the switch housing were loose, this caused the intermittent connection for the dash light rheostat. I could squeeze the switch together and the lights would work.

I swapped it with one from the parts car and everything was fine.

The central locking system was as simple, but no less annoying.

In order to get the keyless entry system to work, I had to add a power solenoid to the driver's door. It was actually very simple once the wiring was done. The new solenoid/lock motor came with a handy rod and a sort of clamp.

Because I had too great of an angle between the new solenoid and the master control switch, it forced the lock rod out of the switch.

I realigned everything and popped the rod back into to the switch and everything was fine.

Thanks for the ideas.