Headlight problem

[440+6]

On my 70 GTX when I turn on my headlights the two outer lights come on like normal, when I turn on my brights they come on fine but the right side headlight goes out, left side stays on.
Are the outer headlights dual filament and I have a bad lamp? Or something else?
I thought they where single filament.
Thanks

 

[PlumcrazyRR]

From just a quick pull up of the basic schematics it looks like it is a dual filament and you may have already answered your question. It has been so long since I have looked at mine, that I couldn't remember for sure. Outer headlight bulb on the bad side is where I would start. Dual filaments will have 3 pins and single filaments should have 2 pins on the lamp for those old ones.

I would think you would be able to use a handheld multimeter to be able to do a continuity check on the back pins of the lamp to see if there is an open in one of the filaments. Or maybe use the known good bulb as a comparison. I could be wrong though, I have never performed a continuity check on one of those older headlamps. In theory it should work though. Typically when the filament goes bad, it burns up, causing an open in the circuit, thus losing your continuity.

http://www.mymopar.com/downloads/1970/70BelvedereGTXSatelliteRoad RunnerA.JPG

 

[Krusty]

They are indeed two filament. If you don't have access to a meter flop the right and left to see if it changes sides.

 

[Xp29h]

When I first got my charger I had the same issue. Low beams ok but hit high and one went out. I found two loose ground wires within the light harness. Cleaned, put back and bingo worked great. Maybe a bulb and/or filament but check your grounds too. My thought...good luck