McD6288

Hi I'm removing my interior harness to check it for shorts.

Where it goes to the fuel pump, do I need to drop my tank and remove stuff from it?

Can I remove the harness without taking out the dash(within reasonable effort)?
Is it significantly easier to remove without the dash, to the point that removing the dash is worth it?

Do I need to cut wires in order to remove this entire harness(from rear lights to front lights?


for those wondering why I'm doing this: My parking lights and dash lights quit working randomly and I left it for about 3 months that way and continued to drive it(the headlights, brake lights, reverse lights, turn signals, hazards all worked fine). I decided to go ahead and try to figure out what was causing my #8 fuse to blow the moment I turned the headlight switch. while digging through the underdash wiring, my rigged fuel pump wiring got pulled out from my main relay(previous owner had a inline fuse wired to the power wire coming out of the main relay, just wrapped around a part of stripped wire and going to the fuel pump somewhere) and my ecm got fried somehow. not really sure what exactly happened but it happened. so I'm pulling the whole thing and figuring out what exactly is going on under there and what could be causing my problem. elaborating on the fuel pump wiring, I have dropped my tank before and replaced my fuel pump, there was no sign I could find of the wire where you pull the pump out, but I could barely see anything down there since I don't have a car lift so idk exactly where it's going.

Any help is appreciated, help diagnosing this monstrosity would be a godsend. I'll be keeping a close eye on this thread, if any pictures would help I am glad to post them.

sumdewd

1: No: The pump and sending unit both connect from under the back seat if I remember.

2: No, then yes: The interior harness is literally mounted to the back of the dash, so you're gonna have an awkward time unscrewing the connector mounts from it when you do unbolt the dash. It needs to be unbolted but may not have to come out fully if you have patience. If you're going that far I would just remove it to service other items in the area (reseal air ducts, etc).

3: Most likely not, unless you cut corners. I've had the whole interior out of my 90 SI HB and never noticed a harness that would require cutting to remove.

I think you need to study a wiring diagram, and think carefully about whether removing the whole harness is worth it VS troubleshooting. Unless you literally have a donor car with the exact harness that's ready to go, I would personally steer clear of it. Your mileage may vary. You may also break several interior parts in the process.

McD6288

Hi McD again, what possibilities come to mind when your parking lights/dash lights keep blowing the fuse? could it be one of the corner lights? or my 3rd brake light? maybe a cluster light or something? when turning the headlight switch, the front corner lights, and rear brake lights come on momentarily before the fuse blows

McD6288

edit:***not***: FIXED!!!!!!!!!!!!!!!!!!!!!!!

license plate light circuit is shorting the whole thing out. probably just gonna wire in a strip of LEDs and stick 'em underneath.

still blowing.... not fixed....

scelestus

How did you determine that the license plate light was the problem? Have you spent any time with diagrams as sumdewd suggested? The license plate light should be on the same circuit that powers all the running lights.

The interior harness terminates to the dash harness on the driver side footwell and runs all the way to the back of the car (on a hatchback anyway)- if the fuel pump wiring has been messed with it's likely that something else has been damaged. A whole lot of continuity testing is in order.

McD6288

I plugged things in one at a time until the circuit blew. it's still blowing even with the license plate lights unplugged so I'm going to replace the bulb sockets for the tail lights the whole wiring from bulb to harness plug

sumdewd

Got a good multimeter? It's time to get dirty and start checking for continuity to ground on all power wires. Make sure you solder and heatshrink. Do not use butt connectors or you'll likely make it worse.