Schematic for 98 SL2? 10 amp body fuse blows

I have a 1998 SL2 and the 10 amp body fuse blows. Tried a 20 amp (danger!) and it immediately blew, too.

The dome light doesn't work, is it on that circuit? The side towards the switch behaves like a switched ground connection:

0 ohms in the 'on' position. 20-25 ohms in 'door' position. open circuit in 'off' position.

The other end of the dome light shows a couple ohms to ground. All of this is with the bulb removed.

Seems like a short to ground somewhere.

Are there any schematics online? I have the Hayes manual and it gives a general guide for a 94, which doesn't really help. I need connector locations and wire colors.

Any ideas?

Thanks!

Reply to
Mikey
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Mikey....

looks like you have a short to the ground somewhere between the fuse and the dome bulb. This fuse also provides power to the MAP lights as well as your trunk light. All three should be affected by your problem. Finding it will be a heck of a project. YOu might get lucky by measuring the resistance from the orange wire to ground on all three lights, whichever is the lowest will indicate that the problem is near there. Wires normally travel in bundles, I can't see the problem occurring there. However, I would try to trace the wires as they leave the bundle and head to their final destination...quite possibly the insulation has been rubbing against a passthrough hole, exposing the wire to car's body.

Good luck

Alex

Reply to
navaidstech

I'll try tracing the wires. The main library for the area has the official Saturn manual, the giant one that costs $$$ and it had some good info.

The instrument panel body fuse feeds the three lights you mentioned along with the door lock switches (which also don't work) and the data link connector.

Here's the bit that seems iffy: The wires come off the back of the fuse panel, all are orange and the manual gives the location of each. If I could take the wires off each circuit could be checked separately. There is a bolt on the back of the fuse panel. Does the fuse panel come apart?

Another possibility is a "fox and hound" circuit tracer. The "fox" generates an audio or RF signal and the "hound" picks it up. Anyway, I'll poke around this weekend and see what's going on.

Thanks!

Reply to
Mikey

Fox and hound might work but you have to be careful as RF from one wire might induce into wires next to it and you will end up with a signal all over the place.

The fuse panel does come apart but I suspect putting it back together would be quite a challenge it it's build the same way as the underhood junction box. UHJB has a network of interconnections inside and I wouldn't even touch it with a 10 foot pole....I might wrong though - the fuse box might be built differently.

If you have sharp DVM probes, you might be able to pierce the insulation of the wire and trace them that way.

Reply to
navaidstech

Spent some time over the weekend. Took off the door lock switches and trunk light to get to the wires. A check with an ohmmeter gave the same (low) value to ground everywhere. Somewhere around 2.5 ohms.

I took off the rear deck cover to get to check the wires back there for cuts (there were none) and cleaned the splice pack connections. After that the resistance to ground was ~1.5 ohms, definitely less than before. Perhaps the short is to ground in the back of the car?

Next plan: Take the 6 orange +12 wires from the body fuse. One at a time, cut the wire, check resistance to ground for that portion of theh circuit, and if good, put in an inline connector.

If it's a short to ground, follow it. If it can't be followed leave it disconnected and tape it up. My guess that just one of the six wires has a short.

Fox and hound usage: What is needed is one that does inductive coupling and can detect current flow. The ones that use RF and capacitive pickup probably won't do it. Too bad most look like they use capacitive pickup.

Reply to
Mikey

There is one more method that would quite accurately pinpoint the location of the problem and it's using a device called a TDR (Time Domain Reflectometer). We use it at work all the time to pinpoint problems in RF transmission lines. It can, quite reliably, tell you how far from the end of the line to look for a short, open or what have you. Unfortunately it's beyond the budget of an average backyard mechanic.

In any case, good luck. Keep me posted what you find. I'll be more than interested to learn where the problem was.

Reply to
navaidstech

We had some nice weather and I found out where it is...

There are 6 circuits off the body fuse. I cut them one at a time and added an inline connector. The problem was with the driver side door lock switch. It is now disconnected and everything else works OK.

Next job is to take the seat out and follow the wire bundle under the carpet and to the door. Or perhaps take the outside door panel out and start from that end. My guess is that it is >There is one more method that would quite accurately pinpoint the

Reply to
Mikey

I was wonderign what was happening with your endeavours. Good stuff, you're almost there.

Reply to
navaidstech

Kid took the car to college. No more work on it until Thanksgiving break.

Reply to
Mikey

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