parshath

I have a 91 4.3 S10 and when I turn on the headlights the engine will stall and won't start back up for at least 10 min. Otherwise it runs perfect. I have pulled most of the wiring out of the plastic covering and they seem fine. The wiring goes from the headlight to a socket on the firewall which I cannot figure out how to remove to inspect. Any thoughts on what is going wrong? By the way everything is fine when it is using the daytime running lights. just not the night lights.

EvansBlue

There is a bridged circuit somewhere.... which means that two wires or connections are making contact where they shouldn't be.

parshath

Would that be specifically in the headlight wiring or could it be anywhere?

dewey

Can you tell if the DRL relay is still energized after you turn on the headlamp switch? It shouldn't be. You might unplug the DRL relay, then see if the headlamps still work? They may not, some of my info shows, when the DRL relay is not energized, the switch side of the relay acts as a ground for the headlamp.

Does the battery have a good charge, are the cables clean on both ends, does the charging system work ok? Are there any codes?

Are you saying, when the problem happens, andthe vehicle dies, it cranks good but won't start?

parshath

I do not know how to retrieve codes. I tried jumping the two connectors like the manual says but I never get the flash codes also where is the DRL relay located? The battery seems good and is not that old all conections are free of corrosion.

Yes the vehicle dies and it will crank perfectly it just wont turn over. I can do this until the battery is almost dead but if I wait a while it will start again with little battery power and will recharge the battery quickly. The trucks runs like new otherwise and I have looked at most of the wiring for wear damage but they all seem good.

Thanks for taking your time guys

moosinatrix

I just bought the same exact truck with the same exact problem. i have discovered that when it does this its shorting out the fuel pump, if i spray starter fluid in throttlbody it will turn over.

I also have no interior lights no headlight or tail light, my turn signals work but parking lights dont.

there was an after market alarm systme in it but the pightail for it wasnt plugged into the little black box for it, when i started it. it started up fun and while checking what works and what doesnt, of course the first thing i check was the light and thats when the engine died.

can anyone tell me where the DRL relay is so i can try doing the unplug it thing.