So back in january, i was in an emergency rush since my other car (prelude)'s alternator decided to wiggle loose. so my prelude was parked in middle of the street and i needed to get it home (8-9 blocks) i couldn't even start the car at that point, so i got a ride home and decided to borrow the s2k's battery. it worked fine and all was well, except that the previous owner of my s2k put the velvet terminal protectors backwards. my dumbass didn't check before putting it back into the s2k and for 1-2seconds it was reverse polaritized? pos to neg and neg to pos, boom! so here we are 8 months later, all the other issues have been resolved. but for some odd reason the headlights are not getting a signal. and i've tried everything i could think of.

symptoms:
when headlight switch is turned to on position, the diffusers will light up, but the low and high beams won't fire up. cluster dims, so the car thinks its headlights on, so its more probable to think its a problem with relay/wiring.

i've tested these things so far:
fuse (swapped in a spare fuse, known-good)
relay (switched it around and tested, no good. will be getting bnib one to test 2m)
switch (replaced with a switch from a wrecked car, was flipped, so doubt it was bad)
hid ballast/bulbs (took them off the car, used a battery charger 12V to apply power and they fired up flawlessly)
i checked the big fuses as well, all good.
grounds (i grounded, and regrounded left and right to no avail.)

im thinking its an issue between the harness itself, and the relay.
even with the relay removed, the lights behave the same.
if not the relay, i really think it's the harness with some fried pins, not making contact and not sending the power from switch to headlights.

anyone got anything for me to check before i call a master electrician out here? thanks

 

It sounds like something has blown and you have an open somewhere in the circuit. Check to make sure the ground side and the power side are both ok. I know you said you grounded and regrounded but make sure your even getting voltage through the wires and start from there.

 

sorry, but what do you mean by groundside and powerside? do you mean the actual battery ground / power? or the headlight ground?

i was actually thinking the same thing since theres no continuity to the headlights , and i'm looking at the wire diagram right now to see which one pins out where. problem is i don't have a probe to use at the moment, but will have one to use in a few hours.

im gonna probe the starting from the switch (the harness/switch), check to the relay and then to the headlights themselves.

thanks for the help

 

Sorry I meant the ground/power for the headlight circuit. I doubt if its the battery if the car itself is running and all the other electrical components are ok.

But from the things you've already checked, checking the circuit itself seems to be the only other logical step I can think of.

And no problem. If you have a wiring diagram that you can reference to that should make it a lot easier to try and locate the problem!

 

for the parts of the relays labeled A, do you think its possible since all the relays i've used to test with were in the car when the battery accident happened that all of them are bridging improperly? im told its very rare to have relays fry, but it does happen.

as for B, has anyone ever had a diode go out? to my understanding of a diode, it just passes current through. but since i reverse the batt terminals could it have been damaged? im assuming since it's part of the circuit that it only accepts the regular 12V current.

 

Have you tried jumping the headlights though the relay connectors directly?

On other words, remove the relay, and jump the connectors directly? Prolly won't work anyway, as you've tried a known good relay...

 

right now im pretty sure its in the harness itself. ill guess there's something i didn't think of and its under the fusebox. oh well.. taking it in 2m

 

bumpz

 

here's something funny to think about, even the shop doing the work can't figure it out..

with a 12V probe
applying 12V through a the harness pin for the headlight itself will fire up the HIDs... since that's the case, does it mean ONLY the switch can be faulty? or can it still be the relay and whatnot?

with that done, it appears the harness-to-fusebox-to-headlight wire is okay. so it narrows it down to switch,relay and ground right?