Here's one for the books. My dash lights, running lights and tail lights don't come on when I try to turn them on. Headlights work, backup lights work, turn signals work, and brake lights work. I pulled the plug from the light switch and jumped from the red [hot] to the green [dash lights] and I got dash lights. I jumped from the red to the brown tail lights/running lights and they work. Plug the plug back into the light switch and they don't work again. I have two brand new switches so I don't thing that is the problem. Any suggestions would be very much appreciated.

 

got a multimeter & a wiring diagram?

ur probably gonna need them.

sounds like separate problems to me, too many different circuits for all of these problems to likely be caused by one problem.

have u had the car long? has it been this way as long as u have had it? did all the problems start together, like meebe after u did some other work? if thats the case id check everything u just did for bad grounds etc

if it was me id check all the fuses, and all the bulbs. use the meter to check continuity through the bulbs

then id take one bunch at a time. the dash lts are all powered off the green as u know, but that green goes into the fusebox, through a 5a fuse, and out as a grey wire which goes to all the bulbs on a 73. im not near my car or diagram so i cant give u much else. theres a grnd on the speedo, tach and i think the gauge cluster. these lts ground to the metal cases. see if these grnds are present,and have continuity back to the battery. then u can start checking for power.

i like to make a test lead w a small clip i attach to the - side of the batt to use for testing. good grounds seem hard to come by in these cars

 

My guess would be a bad headlight switch.

Do they not work in both spots? Do they come on when you pull the headlight switch to the halfway position?

 

I've had the car for 3 years and put new wiring harness in. Also, I bought a new headlight switch today. About a week ago I was out and turned on the lights and they didn't work, half way home they came on. Next time I used the car, the gauge lights and tail lights didn't work and haven't worked since. I just don't understand why it works if I jump the wires at the switch, but not with a good headlight switch hooked up.