Dual headlight issue

[Magic1]

On my 82 Sierra I have the dual headlight setup and when the low beams are on there is a small draw on the high beams. The bulbs are barely lit. I've replaced the headlight switch and dimmer switch as well as completely rewired the truck with a kit from Painless. I just recently replaced the dimmer switch because when I was driving at night with the lights on high they would start to flicker on and off but once I put them back to low it would quit. I haven't been able to see if it fixed the problem  because I haven't driven it at night again yet. I have the headlights run to grounds on each side. I'm thinking its one of two things: 1 the grounds aren't big enough or 2 with both sets of headlights being on bright it's overloading the circuit somehow and getting the wiring hot. Anybody else have an idea?

[bd]

The headlamps flickering on-and-off with high beam is most likely the headlamp switch due to an integrated, non-serviceable circuit breaker that is built into the switch.  The high beam filaments glowing on low beam is most likely a poor ground.  Try running a temporary jumper between the radiator support and battery ground to see if the symptoms go away.  Make sure all your ground connections are clean and not insulated through a layer of paint.

[Magic1]

Ok. Ill check the grounds as soon as I get a chance. As far as the flickering you think it's a bad headlight switch even though it was recently replaced and not the dimmer switch? I figured it to be the dimmer since it only did it on highbeams.

[bd]

I made an assumption about the cause based on the symptoms you posted.  You can verify the cause by taking voltage drop tests when the symptoms are active. 

With the headlamps on high beam, maximum current passes through the integrated circuit breaker.  GM had a 'problem' with their headlamp switches in that the switches were stressed to their limit.  If you upgraded your headlamps so they pull more current than the originals, the circuit breakers would cycle from overload.  In some cases, the headlamps would cycle even under normal circumstances.  The solution in such cases is to install a high beam relay.

[Magic1]

Makes sense bd. ill give it a try. Thanks for the help!

[pholliday1]

If you continue to battle with this, you can run a relay setup with your high and low beam wires being control voltage. Bd is the master of this setup. If you decide to go this route I'm sure he wouldn't mind helping you.