Headlights / grounding

[82LTDQS]

Should all 4 headlights ( 2 low/high and 2 high only ) have their own individual ground??? When I re-did the wiring for mine, I used on large common ground wire hooked to all four lights to avoid multiple ground sites. This common ground goes to the frame. Should I not have done this? Here is why Im asking: My head lights work fine, but when I hit my high beams, only the aux (high only) lights come on. The main head lights (in high mode) go very dim. So I have 2 bright ones and two dim ones. I unplugged my left side headlights and then the ones on the right worked perfectly as they should. As if they are starving for power or ground. Any advice?

[85crownHPP]

each side has its own ground from the factory, but it should be fine the way you did it as long as they are wired right. prolly just something you overlooked in your wiring...

Have someone flash the high beams with the headlight switch off and see what they do then.

[82LTDQS]

K, will do bro.

[91waggin]

When you turn the high beams on, the low beams will get a little dimmer, because you're switching to a different filament inside the bulb. But if it's getting a lot dimmer (like unusably dim) then you've got problems.

1. Double-check your wiring and connections. It's easy to miss shit.

2. You can find out whether the low beams are starving for ground simply by running a temporary jumper from the ground terminal on one low-beam to the negative battery terminal. If that fixes the problem on one side, you know that's your problem and you should probably give the low beam its own ground.

You could also unplug the high-beam only from one side and see if the low-beam on that side or both sides gets brighter.

3. What gauge wire did you run for your common ground for all four lights? Perhaps it's simply not beefy enough. (I would guess that this is the case, since unplugging one side seemed to help.) Is the ground wire getting really hot with all four lights on?

[82LTDQS]

In my experience with four headlight cars, the main headlight has a low and high beam filament and the other light is only a high beam. They should all be just as bright when they are in high mode(all 4). However, in my case, my main lights do become unusably dim in high beam mode, yet my second lights (high beams only) are just fine. I did the jumper test and it failed, so i guess its not on the ground side. the wires are the factory FORD wiring harnes mated to the Pontiac harness just before the headlights. I used crimps. could that be the problem??? Im gona try unplugging the high only ;ike you advised. If that doesnt work I give the lowes their own ground. Thanks for the help bro. I will let you know how it works out.

[gabegt90]

you give all them there own ground. ford had a stupid way of ground the lights on boxes just a tinny little ground wire for both sides of the car bolted to the fender

[82LTDQS]

Im gona have to.

[91waggin]

Also get rid of the crimps or add solder to the crimps. I never do anything with an amperage-sensitive application with anything but solder, because it ends up working so much better in the long run.