Hi Guys,

I have a 77....Headlights and Brake lights work fine as well as Turn Signals, but no Tail or side marker lights. The fuse seems to be good for Tail as well...Any Ideas?

It's most likely a ground issue.  The rear harness has a black wire that should be grounded to the frame at the rear of the car.  See if it's corroded or broken.

There is a plug on the harness (usually beside the fuse box) that goes to the rear harness.  Check and make sure it's plugged in.  It provides continuity to your fuel gauge as well, so if that's not working, it could be another clue...  It also shares a ground with the taillights and side markers.

... never mind... just reread your post, and realized your brake lights were working  Ground wire won't do it.

But there is a brown wire that's in the harness to the rear of the car that supplies tails, license plate lights, and side markers.  See if it's OK.


|UPDATED|8/22/2013 6:52:10 PM (AZT)|/UPDATED|

Thanks, I will check out the Brown wire, just a question...does the brown wire power the front side marker lights as well? And what are the thoughts on the headlight switch?

This should help you see what's going on It has to be at the the connector or the ground the rear is separate

Did you check to see if you had power to the bulb socket contacts?

Looking at the diagram, the front and rear connections for park/tail are different wires, but they come from the same connection on the light switch.  So I wouldn't tear up the dash to get to the light switch just yet.

If you are handy with a voltmeter, unplug the rear harness connector (a little over an inch wide) down by the fuse box.  Turn on the lights and see if you have 12v at the brown wire.  That will at least tell you if you if the light switch is getting voltage to the harness.