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!

 

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

 

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!

 

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.

 

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.

 

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.

 

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 in the door or where
the wires go into the body - that's where they move the most and it is
an intermittent problem.

 

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

 

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