Left headlight only flickers above 30-35mph up to 90+mph. New lights, have tried unplugging motors to make sure wasn't moving, unplugged light and other is fine. Even worse when switch to high beams. Have checked grounds. Running out of ideas.....

Guess I have to tell- 88 Trans Am GTA with digital dash...

 

You've said you checked grounds. Check, check and recheck. I believe each light assembly has it's own ground. Only other thing I would think it could be is the connection plug(s), rarely do they come loose though.

 

Actually made it's own ground, so I am sure that is not it. Also, I have check and cleaned the light pigtail.

Help!

 

Try a smear of dielectric grease on the plugs.

JamesC

 

Yup, done that. Not it. Has something to do with speed.....

 

It's obviously a bad connection because speed has nothing to do with it.I would recommend turning them on in the drive way and just shake the wire bundle to recreate it and narrow it down from there.One of your wires could be broken inside the insulation probably at the pivot point.If you don't have other problems with turn signals or something else it probably isn't ground but power.Headlights will usually seek ground through the turn signals and be dim.

 

voltage regulator maybe? when they go bad lights go in and out

 

Replaced the alternator already (under warranty so free), and have jiggled the wires as best I could. Need to inspect the entire harness which is involved in the firebirds with the digital dash....

 

inspect the plug since that is most likely the culprit.The sockets may look good but be intermittant.Pop them out of the plug and bend them back in shape.Most of the time it's a simple fix for something like this.The headlights on mine wouldn't pop up sometimes,i found the ground for both and now their fine.You could try a new bulb.Perhaps that one is bad.I've seen stranger things.hope this helps.