Whoa here is a good one for the pro's...

My brother has a 90 CRX with the ZC swap already done when he got the car. It ran fine and had no issues up until a few days ago. Here is what happens...

When the problem first surfaced, the tail lights and gauge cluster lights went out. Keep in mind the lights DID light up if he hit the brake though. He tried about 5 different fuses, and every single one blew on that particular circuit. He wanted me to take a look at it, so I got underneath the dash and double checked everything, and put a fuse in the fusebox, and it mysteriously worked.

Fast forward to this morning... the car now has daytime running tail lights. As soon as the key is turned to the 'accessory' position, the the tail lights come on. Hit the brakes and they get brighter. Fuse is not blowing, its just that as soon as you turn the key on, the tail lights and gauge cluster lights come on. There was a yellow wire with small silver markings on it that game out of the front of the fuse box... here are a couple of pictures...





Its the wire coming out of the blue plug.



Same thing... its the wire coming out of teh blue plug.

If you look closely, you can see that the wire is taped up a little bit. It looks like the wire, at one point, got really hot and over heated. I just taped it up to prevent it from grounding out.

I have no clue what the wire is actually used for or if the wire and the tail light problem are connected, but thats why i'm turning to you guys. Any ideas?

 

anybody? I just want to find out exactly what that yellow wire is.

 

I didnt see it in any wiring diagrams that I have... pull the plug and then turn the car to on and see if the lights come on.

 

Check your grounds. Specially the ones in the engine bay i.e. the wire from the battery to the body.

 

ok...i will take a shot.
aftermarket radio with adapter harness.
i work at a dealer and have seen more light problems caused by this than anything else. check the wires. tape loose ends

 

Heres the wiring diagram, did not have time to go over it but take a look for yourself

 

This one is easy.

Not that im telling you this is what your problem is but SOMEWHERE.....you've got open wire shorting to ground and power at different times.

the taillights and gauge cluster are both ground side switches that means power goes through the load(the light) then grounds itself out, if at any time the wiring or bulb(this could be yoru problem) gets shorted whether before the load(short to power everything will be on even when its supposed to be off, as long as power is supplied to the circuit) or short to ground its after the load and the circuit does not ground properly voltage goes through the load goes to ground but it has no ground so it backfeeds through the load and the circuit protector for this situation breaks(Your fuse) creating an open and saving the circuit from any more harm.

If you can get it to work do a wiggle test grab the harness for the taillights or the harness's in the engine(for the gauge cluster) wait to see if you either blow the fuse or the problem goes away(the lights shut off when they are supposed to)

I could tell you all about wonderful voltage drops unless you already know how to do them, but you now have a wiring diagram so if you know how to properly test a circuit and know what your expected voltage should be then you know what to look for.

if you have any more ?'s just ask.

 

ps I forgot to mention take your gauge cluster out and inspect the circuit board on the back, it could be shorted to ground/power.......now that I think of it that is really what im thinking, I assume everything in the gauge cluster works fine.

 

My car did something like that, and after pulling my hole dash I found that one of the wires from the radio to the fuse box got so hot it melted it and the wires a round it and shorted all of my lights.

 

Basically the wire that isnt attached is supposed to be grounded. Since it is not, the current is backfeeding through those components which seem as though they are malfunctioning in order to ground out and complete the circuit. Attach the black wire back into the location it was originally.