I just finished a major overhaul of my electrical system and have a very strange problem. When I hook up the black horn trigger wire to the horn relay, the front fender park lights (little side markers) come on right away. They come on without anything being turned on and even without fuses in the fuse box!!
I was told that it sounds like a ground problem, but I think my grounds are ok.

Mike

Do your front parking lights, rear taillights, license light and rear side marker lights come on at the same time as the front marker lights? All those lamps are fed by two dedicated 20-ga. brown wires from a single terminal on the headlight switch (one wire to the front through the fuse block, the other to the body connector to the rear lights) - when that wire gets power, all those lights have to come on. graemlins/thumbsup.gif

No John, only the front marker lights come on. All the rear lights are working properly. The front park lights are not working although their is power coming to the connector for these lights (and the bulbs are not blown). I still have more troubleshooting to do, however I decided to forego the lights for a few days so that I could put my energy into getting my 408 started up for the first time! I started it on Wednesday night (see Performance thread) Anyway, in the mean time I just figured I would throw this problem out to see what it could be. I just don't understand how the horn trigger wire, which, if the horn button is not being depressed, should just be a dead wire, not pos or neg, can make my front side marker lights come on! This problem only started after installing new dash harness.

Mike

I don't know how the horn trigger wire would get power to only the front marker lamps either, but the terminal on the horn relay the horn trigger wire plugs into is hot all the time - when you ground the trigger wire (like the horn button does when you push it), it energizes the relay coil in the horn relay. graemlins/thumbsup.gif

Check your Passenger Fender to Battery Negative ground, also you must have your fenders/inner fenders all bolted up to the radiator support for ground to work properly since its isolated via rubber/poly bushings. Also check your engine to firewall grounds.

Thanks Brian, I will check all of those. I won't get to it for a few days, but I will let you know how I make out. Thanks again.

Mike