interior light short

johndfw · #1 (**permalink**) 10-02-05, 10:05 PM

Hey folks

Anyone know how to track down a short at the interior light cir.?
I replaced the fuse and it blew once I got going.

Any help would be appreciated

Eldyfig · #2 (**permalink**) 10-02-05, 11:21 PM

What car?

Have you recently done any work or experienced something that might have caused a short?

I had a short recently caused by the wind catching my trunk lid after I opened it from inside the vehicle. As the lid came up, the wind forced it up harder. I found two wires shorted in the harness from the trunk lid to the trunk...two months later.

johndfw · #3 (**permalink**) 10-03-05, 11:32 AM

Hey Eldyfig

Its an 87 brougham (307). I bought the car with the interior lights not working. I replaced the burned fuse and they worked. When I got back in the car 10 min. later, they were back out. I think I might have some loose wires behined the dash, Im not sure where to start

Eldyfig · #4 (**permalink**) 10-03-05, 02:13 PM

Factory stereo or aftermarket? The previous owner may have dove work on it somewhere and may have pinched a wire.

johndfw · #5 (**permalink**) 10-03-05, 02:48 PM

Factory

ccclarke · #6 (**permalink**) 10-05-05, 12:10 AM

Here's a little trick I've used countless times to find shorts in fused circuits:

Since the fuse blows and you know you have a dead short, start by pulling the fuse and connect one side of the ohmeter to the shorted side (not power) of the fused circuit. Clip the other lead to a good ground and you should get 0 ohms or very low resistance (this verifies your shorted condition without having to use a fuse). If the ohmeter has a tone to verify ) ohms, start wiggling your wires in the lighting circuits, documenting everything as you progress. For interior lighting shorts, look carefully around the door switches and wiring of the harness where it goes between the door and car for signs of chaffing. Cycle the doors while watching the ohmeter, etc. Keep at it until you isolate the short. The ohmeter is a great tool, but your eyes may find it just as easily! Good luck!
CC

Eldyfig · #7 (**permalink**) 10-05-05, 12:15 AM

I like that. It sounds very useful. I hope I remember it the next time I have a short. It would also give me an excuse to upgrade my current multimeter to a better one with a tone alert.

johndfw · #8 (**permalink**) 10-09-05, 12:34 AM

Hey folks
I pulled the radio..........there has been some monkey business. It looks as though the original radio has been put back in. A factory connector has been spliced in to hook up to the radio. Also ......the radio has a lot of places for plugs ect.....It seems like way to many conections go through the radio.

Any thoughts would be helpful

thanks

ccclarke · #9 (**permalink**) 10-09-05, 03:21 AM

Let's stick with the original fault which may or may not have anything to do with a previous radio replacement. With the radio disconnected, does the lighting problem go away?

johndfw · #10 (**permalink**) 10-09-05, 03:10 PM

ccc.....No it didnt go away. I was hoping to find an obvious short behind the radio.

ccclarke · #11 (**permalink**) 10-09-05, 08:00 PM

Okay, let's start with the basics; this problem HAS to be driving (no pun intended) you nuts already. . . When you pop in a new fuse, idoes it blow instantly? If not, does activating some portion of the lighting circuit cause the fuse to blow? --Headlights, door switch closing, etc. If the fuse blows instantly, if you place a multi-meter on the shorted side (not the power side, or you get to buy new fuses for your multi-meter!) of the fuse holder (--just to play it safe and avoid measuring the wrong test point, make sure the fuse is removed, too!) what kind of resistance reading are you seeing? --This is to check for a dead short (0 ohms) as opposed to low resistance. Okay. . . it's time to play twenty quetions now: What work has been done on the vehicle lately? When did you first notice the problem? Was it intermittent, or did it occur and never go away? If it did appear and take up residence, what were you doing when you first noticed it? Report back and we'll continue!

--No problems, just solutions awaiting discovery! CC

johndfw · #12 (**permalink**) 10-10-05, 11:45 AM

Thanks ccc

The car had the problem when I bought it last week. The first thing I did was check the fuse (body fuse). It was blown, so I replaced it. All the lights worked. I went inside to get somthing and came back out to go home,and noticed the lights didnt work again. The drivers door was opened when I istalled the fuse, and I closed it when I went inside. (all in about 5 min.)
Now the fuse blows as soon as I install it. I havent done anything on that circuit.
I made a test light that I put in place of the fuse. It lights up. I was told when I unplug the shorted component that the light would go out, but thats a lot of lights to check.

Later

Eldyfig · #13 (**permalink**) 10-10-05, 12:00 PM

I have one of those fuse test lights...plugs right into the fuse holder and has a small bulb on top of it. They work in helping find a short. It has came in handy.

Do you have a multimeter like cc mentioned?

johndfw · #14 (**permalink**) 10-10-05, 02:46 PM

Eldyfig
I do have a multimeter......just not sure where to start.

Eldyfig · #15 (**permalink**) 10-10-05, 09:30 PM

I don't have one, but I have seen devices at the tool store and my father mentioned he has one...a short finder. CC, have you used one of these?

I think you should start pulling bulbs.