electrical question

ok my buddy bought a 88 6 cyl
hes getting constant power to the front headlight and tailight harness but with new lights in the lights dont light up
he replaced the headlight switch
what else could be caused by this ?

Schematic looks like it feeds power from battery, to headlight switch, then through the hi/lo beam select switch to the headlights. So check beam select switch and all associated wiring.

I know that's what the schematic says. I wanna know why power is going through the head light wiring harness when I replaced the switch and the main relay has been disconnected. If anyone has any good ideas please let me or speedbump know

Sorry, but I, for one, am not too clear about what you are saying, other than lights not working well. Test/probe sockets with a voltmeter, if not satisfactory.., disconnect your battery, clean your sockets,(old point file, or small screwdriver, etc.), and clean associated grounds, and again test with a voltmeter. Before re-installing bulb connection into socket try another pre-emptive test by connecting some wire to negative prong on headlight, then to ground, and with another wire check the high beam to the positive post on the battery.., then the low. That last thought is just to make sure that you do not have a defective chi-com bulb(s). If that process of elimination shows no power to your sockets.., then you must ...search along wires, as per your diagrams. Ever notice that vehicle coming at you where the lights blink off momentarily on a rutted road? Bad ground in the lighting wires, or a short. Bad hi/low beam switch will cause the lights to go out. Happened to me on a curve with a clift at 45mph, stopped quickly.., pulled out a flash light and drove to a safe place to fix the switch. Hmmm.., old days, lol, floor mounted beam switch. (Hellava easier switch to fix!).

So, what new lamps did you put in? New headlights? If your problem started after you put in new headlights, then you need to take those out and put the old lights back in. If the condition then disappears then the new lights are screwing up the circuit. This is what I'd do, anyway.

External lights are supposed to be constant ground with switched power, so if you have constant power you have a problem

is it possible that someone has wired an aftermarket harness into this thing? I could see constant power to the relay being switched by the headlamp switch in that case.

i dont see the harness being cut anywhere the guy that he bought it from tried to wire in 2 120 amp pro comp lights into the factory fog light harness we had pulled the relay conector off the firewall and looked at the bottom of it it looks all melted the guy he bought it from said he saw smoke and then tried turning the headlights and tail lights the next day and they didnt work he doesnt have any running brake or headlights but power to the sockets where the lights plug into. so he has constant power with the switch off

would have been nice to have all the details up front.

two problems...

1. If he has constant power with the switch off then the harness has a short circuit to power.

2. If he has constant power with no lights then the ground circuit burned open.

Get out the meter and check out the circuit if you know how to use a meter, trace wires and read the schematic.

If you can't do that, bring it to the shop.