High Beam Headlight's refuse to work

#1

I am the Proud Owner of a '72 chevy 3/4 ton p/u I installed a new floor dimmer switch with the dumb idea that it was bad, cause when I hit the switch to engage the High beam’s the truck laugh’s at me and sez NO High beam’s for You!! And the light’s go plum out except for the park-light’s which makes it difficult to see. I am Hoping there is someone out there in the world of this website thing that can Help me Out, I would deeply Appreciate it Thank You so Much, Sincerely Littlefeather

#2

It is entirely possible that BOTH of your bulbs have burned out high beam filaments. One went out last month, and you didn’t notice because the other one was still good. Now they are both gone. You can check the circuit with a test light, to see if it still has juice to it, or buy one bulb and see if it fixes one side. If it does, buy the other. If it doesn’t, now you have a big round extra.

#3

MG may well be right. It certainly happens. You also could have a bad connection or bad ground, but if it has a relay controlling those lights, that would be the second thing to check after trying replacing at least one of the lamps.

#4

Test the headlights themselves first. If the high beam filaments are burned out there’s your problem. Is there a relay for the high beams? If so, check it. Also make sure the fuses are not burned out. Test the wiring for continuity.