Just replaced main dash harness is a '70 Cutlass SX. Headlights, wipers, top etc. all work and car will start. Courtesy lights come on when door opens as well. Then when I connect accessory harness (plugs into main harness and has a single ground) once that is connected and it's two metal light sockets are snapped into the lower metal dash, if they have bulbs, when either door is opened the fuse to the accessory circuit blows.

I tested the metal sockets and there are two wires; orange and white. Orange is hot all the time and the white grounds when the doors are opened.

Any ideas on what could be going on?

Thanks,
Michael

 

You have a short somewhere in that harness.

 

Which harness, the main or accessory? I've actually tried two accessory harnesses with the same result. So I am thinking the issue is with the main harness but it's brand new from Fusick and am not looking forward to finding a short in it :-(

-Michael

 

The orange wire as you said is a constant non-switched 12v supply. The white wire is connected to the door jamb pin switch circuit. Are those the only 2 wires in the harness?

 

Worth noting is the dash harness that I removed from the car used the spaded door jam switches that only have a single wire. The new harness from Fusick used a pin style door jam switch that has 3 wires going to drivers door (black, white and white with black stripe) and 2 going to passenger side (white, white and black stripe).

-Michael

 

Digging into the schematics, the new main harness looks correct. The 3 wires on LH jamb switch are black for Door Key Buzzer (which works), a white and white w/black stripe.

Black goes to key buzzer
white goes to main light switch, LH and RH jamb switches and dome/opera lights (work when door opens)
White/black stripe goes to LH and RH jamb switches, courtesy and map lights (the courtesy circuit is the one that blows the fuse)

The fuse blows when the door opens and when that happens the white and black, using my Power Probe, goes to ground.

 

Ohming a light circuit to ground won't work as the remaining laps will indicate a short.

If every thing works without the harness plugged in with no fuse blowing then the issue is withing the harness or how you hooked it up. Make sure the wires on the light socket that I'm assuming bolts to ground are not reversed enabling the hot to short to ground when you bolt them in place.

 

In the end it was a due to a single contact bulb being used in a dual contact socket.

-Michael

 

Which light was it?

 

Wow, the singles usually won't plug into a dual socket.

 

Yeah, the lugs have different depths on one and the same depth on the other to prevent insertion into the wrong socket.