Celica Forums General Discussion Interior Dome Circuit Short

I'm fairly certain I have a short in the dome circuit of my '03 Celica. It's causing a parasitic drain on the battery. It dropped a brand new battery to about 8A in a matter of a few days. That circuit is on this fuse (in the interior fuse box by the passenger floorboard):

41. a. MPX-B 7.5 A: Wireless remote control system
b. RR FOG 7.5 A: No circuit
c. DOME 7.5 A: Clock, interior lights
d. ECU- B 7.5 A: Air conditioning system, gauges and meters

I've connected the individual circuits one by one, checking amp draw on the battery. Neither a or b drew any current, and d drew a little extra (about 0.1A), but c drew 0.4A by itself. I haven't ruled out d as part of the problem, but I'm focusing on c first.

Unfortunately, I have no idea where along the line my problem might be. I'm looking for any advice on tracking it down.

I've removed the after-market stereo, and peeked around behind it. I don't see any damaged or pinched wires.

It's also worth mentioning that the front right quarter of this car had to be rebuilt pretty significantly. I suspected that the passenger door sensor was the problem, but fiddling with that and testing the draw hasn't yielded anything conclusive. Still, with only one wire going into the thing, I don't even understand how it works.

So... any tips?

Hey, welcome.

Finding a short doesn't have to be difficult. All you need a test light with a lead. Nothing special, something like this $4 one is fine (https://www.harborfreight.com/612v-circuit-tester-with-5-ft-lead-61652.html).

What you'll need to do is clip the lead to the negative terminal wire and keep the point in contact with the negative terminal. Then you'll want to pull each fuse, one at a time to figure out which circuit is hiding the short. You'll know you've found the short when the test light goes out. In other words, the test light will stay on until you pull the fuse that's connected to the shorted circuit.

This site outlines that process well: http://www.inliners.org/tech/tech6.html

That's how I've always done it. Good luck!

-Connor

Yeah, I have a meter, and I've already narrowed it down to the circuit. But now what? I need to fix that circuit and don't know what to do next.

I'm giving it over to a mechanic tomorrow, who's going to charge $85/hr until he finds and fixes it. I don't really have another option at this point. There is a ton of help on the internet for getting to the point I'm at now, but nothing for what to do next.

Replace the circuit yourself. I did it for the climate control backlighting. Shouldn't be a huge task.

"Shouldn't be a huge task." I'm not sure if our definitions of huge are different, or if I don't understand the scope of work. I'm imagining pulling off half of the interior panels of the car, running a few dozen feet of wire throughout, and hoping I get all of the connections solid. No thanks. I'd rather pay the hourly rate to have someone else do that.

I understand where you're coming from. Guess I'm just cheap lol.

Any directions on changing the climate control backlight would be great, mine quit after changing my Radio/CD, nothing else seems affected.

Hey, welcome!

I blew my climate control backlighting after messing with some other things and found the following links to be useful. Check out these old threads:

https://celicahobby.com/forums/ubbt...-dont-work-are-they-fried.html#Post86523

^That one should be applicable. Be sure to check those multifuses. If you need one, I have a bunch.

Here's the fuse box diagram:

https://celicahobby.com/forums/ubbt...e-room-and-center-junction-diagrams.html

-Connor