Trailer lights problem

I installed a trailer light harness adapter into my 91 Caprice. I grounded the wire in the trunk on the left side bracket where the trunk lid arm attaches as there was already a ground there for something else. When I connect the trailer lights I only have one weak lamp and no signals. I also installed a HD electronic flasher. Is there a problem with grounding in the trunk or have I missed something? Thanks.

I would think that would work. I put a cd changer in my 86's trunk and grounded it in the same place I think you talking about. I did have to scrap the paint there down to bare metal to get a good ground. You might try that to insure you're getting a good ground there.

As far a only having one weak lamp, I'm not quiet sure (there must be a spot in your circuit with a higher than normal resistance resulting in less than adequate voltage across the light, whether that is a bad ground or faulty wiring I'm not sure). Do the lights share the same ground? If so, then that would seem to indicate a decent ground and point to wiring to the individual light being suspect.

As far as no signals, your flasher relay is designed for a certain resistance across it and the lights in series with it (the lights are in parallel with each other but in series with the flasher). Check out the following link:

http://knology.net/~rkmason/flashers.htm

By adding or removing lights in parallel (adding trailer lights), you can change the resistance and thus the voltage drop across the flasher and lights, altering operation (unless your flasher is designed for that voltage). You said you installed a HD (heavy duty) flasher, but is it designed for a trailer lights?

Hope this helps.

After much fiddling around and grounding everything in sight, I found the problem was the connection point for the adapter harness. The instructions showed the connection to be at the trunk lid hinge; and there is one there, and I connected to that one, but that was the problem, there's another connector further back near the back left corner. That was the correct connector. Now everything works fine, finally!! Thanks for the help and suggestions.

BTW, the flasher (Tridon, but don't know the model) is good for up to 12 lamps and can be used for signal or emergency lamps.