nottoshabi

The low beam heads lights decided not to work any more. They work in high beam but not low, which is confusing cause that means there is current going to the bulbs and the bulbs are functional. I googled this problem to see if any one has ran into this before and there is not much out there. Some have mentioned the relay under the dash behind the fuse box. I checked with Toyota that part is no longer being made and they could not tell me any information on the relay. I have no issue replacing it a 4 prong relay is $5 but I don't know the voltage or amp it takes. I did inspect the relay it self and it look good clean and the slapstick shrink wrap is still around it. I need some help on this I dont know what to do. Right now im driving around with the high beams on all time it im going to unplug the inner bulbs so the cops wont give me a ticket for high beam driving.1978 toyota pick up hilux 20R

akwheeler

if you look at your headlight connector I'm pretty sure you will find 3 wires and the bulb will have 3 spades on the back. that means there are two fillaments in each bulb and therefore your theory about " They work in high beam but not low, which is confusing cause that means there is current going to the bulbs and the bulbs are functional." is false and you could very easily have lost one low beam months ago and the other just burned out.
If you don't try putting a meter on both the low and high circuits at the bulb or at least apply power and ground to both the low and high spades on the bulb you have not ruled out the bulb as a problem.
I keep a spare sealed beam bulb in my shop and I just plug it in as a test if I have any question, try that.
you will probably find that you just need two bulbs. either that or a fuse.

akwheeler

Maybe I should clarify a little more, if you have 4 sealed beam headlights on your truck the inner ones will be high beam only and have two wires and two spades (only come on when your high beams are activated) and your outer two will have 3 wires to 3 prongs where one is ground, one is positive for low beam and the other is positive for high beam.
So if you plug a new low beam bulb in or check the low beam fuse you may save yourself a lot of troubleshooting.

nottoshabi

Thanks for the clarification. I ordered 2 bulbs should come in on Friday I will test out your suggestions.