70 GS conv. interior lights fuse

[mullyclu]

The 20 amp fuse blows and the 4 interior lights ( front courtesys & rear armrest flush mounted light) don't work. Glove box light works properly. Both door contact switches are brand new, any ideas on what to check? Either a short or a ground somewhere but how do I proceed?

Thanks,
Steve

[raycow]

Check the easy one first. Remove all 4 bulbs. Now look at the bulbs to see if you have any single contact bulbs in a double contact socket.

Ray

[mullyclu]

Thanks Ray, I will try that 1st.

[mullyclu]

Well, I found the reverse, a bulb with 2 contacts in a courtesy fixture with one centered contact.

[raycow]

Well that's one I sure wasn't expecting. Does the fuse still blow with all 4 bulbs removed? You can save the cost of fuses by checking across the fuse contacts with a multimeter set on volts. Don't use the amp setting, as you might damage the meter if a short circuit is still present.

Ray

[mullyclu]

I thought I had it solved with that simple bulb change, but no, still blew. Maybe tomorrow I can check to see if blows with all bulbs out. These things can be tricky. I'm not that electrical minded but i will get a meter to check across fuse holder without fuse to see what is up. One more note, the cigarette lighter is one this same 20 amp fuse, I bet there is something going on with it, in fact, I might just disconnect it as they can be fire hazards in these older cars.
I do appreciate your help/suggestions.

Steve

[raycow]

That's a good idea. Disconnect the lighter along with anything else which is fed from the same fuse. This will make it much easier to troubleshoot.

Ray

[Rivman]

There is also, or should be, a thermal type fuse at the base of the lighter - that may be the culprit !!