Lights out - help me troubleshoot

[CamB]

Well, the headlights have packed up and gone home on the '69T. I will set out what I have figured out and I would like opinions on whether I have figured out the issue...

First up - background - the lights (incl. park lights and dash lights) are running through the switch - no relays I can figure out for certain. However, it does appear to have been modified so the main power feed to the light switch is fused (a good thing as it turns out). This fuse now blows when the lights are pulled out (to either the park or full position).

Looking at the switch, there are a lot of connectors! I have individually tested each item by unplugging it and giving it 12v. I can confirm that:

- headlights work (low and high beam from indicator signal)
- park lights work (left and right side)
- dash lights work
- licence plate lights work
- little high beam indicator in speedo works

I think that is everything. I also don't think the power lead has a short between fuse box and light switch. There is nothing left but the light switch itself!

BUT, it doesn't make sense that the light switch will cause a short... All it does is pass through +12v to each of (some of to be more correct) the items above when pulled out. There are no ground connections to it (well, technically the lights are "ground") that I can see.

So, is it the switch? What happens when they toast themselves?

Thanks
Cam

[nostatic]

Could it actually be a bad turn signal switch? My lighting problems were mostly due to that, with a fried rheostat in the light switch thrown in for good measure. The only physical symptom was the light switch spun too easily, and it didn't dim the interior lights.

[CamB]

Thanks Todd.

The turn signals still work, as does the high/low beam. I figure (hope) it is ok.

I can't test the dimmer because to test it I have to pull the light switch out and BOOOOOM goes the fuse .

[Early_S_Man]

Cam,

Take a pic or draw a color-coded diagram ... and take all of the load wires off the switch. Pull the switch on and see if the fuse blows ... I think you will have your answer, then!

[CamB]

Thanks Warrren - that's even better than my next plan of taking all but the power wire and one (any) other, then doing the same trick 'till I find the offending circuit.

I'll try both.

Cam

[CamB]

Well, I tried Warren's plan (fine) then mine (also fine). Odd.

So I put the switch back in place and checked the lights. Everything fine (odd).

Upgraded fuse in front of car from 8 amp (for test purposes) to 25 amp. Checked lights again - working - wooohoo (but still a little odd 'cause I've done nothing).

Freaking master cylinder still has miniscule slow leak, but ok to drive (I hope). Need to test.

Start her up, drive off. Its dusk - turn on lights (which work - still odd, but happy).

Just thinking about joining motorway with foot to floor to savour 250hp/tonne, showing my buddy who was assisting me with stuff on my cars today. Notice smoke from "in" dash in front of me. Ferk! Shut of lights very quick. Pull over almost as quick (brakes nearly lock - they work ). Shut off, notice smoke gone, so must be light related... pull fuse up front and drive home before its dark.

Think more urgent thoughts about mounting the fire extinguisher which is sitting on the floor in the garage...

So. I have some more trouble shooting to do. Obviously, it looks like a wire is shorting somewhere, but it could still be a light switch internal issue.

I'll ask back here for help soon. I gotta have another look and I have too much work to do. Live to work or work to live? I can't decide right now.