sjester

Truck is a 95 auto with an overhead console (temperature and compass only)

1) For those that have worked on overheads on the older 2 gens, does the wiring go through the PCM at all?

2) How would I test the temperature sensor with a multimeter? All I'm getting is "SC" for the temp, compass is spot on. Has any one seen the SC?

3) For those that have dug into the steering wheel working on the cruise control, are there any intermediate cruise control connections in the steering wheel other than the 4 pin connector that attaches directly to the switch?

Any info appreciated. I appreciate your indulgence, I'm going to work on locating a service manual in the next few days, Thanks and take care.

Steve

camelracer

I don't believe the PCM is involved with the overhead display on the early 2nd gens. The SC displayed means short circuit. The resistance of the sensor should be 336kohm @ -40C and 2.48kohm @ 55C. Anything less than 2.48 kohm will display SC. The short could be either be in the wiring or a bad sensor.

J BODY

Unplug the temp sensor and if your lucky the temp reading will go "OC" for open circuit. At that point buy a new temp sensor.

sjester

I unplugged it and it remained SC so the sensor is likely OK with a short somewhere. I will check the sensor just in case. I'm also having a problem with the cruise that started at the same time (alot of diagnostics already done) so perhaps these problems are related.

I wonder if these two systems have anything in common electrically? I've also experienced an intermittent failure of the 20 amp horn fuse under the hood. Hopefully I will have a service manual soon, but any help from someone with a wiring diagram would be greatly appreciated.

Thank you very much for the meaning of SC. I thought of a lot of things but that wasn't one of them!!

Thanks again for all the great help here

Steve

infidel

The two systems have nothing in common except that the wires travel though the same loom. Could be something damaged them both at the same time.

sjester

Well that certainly sounds like a possibility given an IOD fuse loss just prior to problems with both systems. Just need to get the wiring diagram now

sjester

Well it may be a first but my cruise control problem was resolved with a new PCM. I ended up taking it to a dealer due to some emergency travel and they showed me the results of a PCM-cruise test from the diagnostics manual, PCM failed the test and it now works with a new one.

I'm still chasing my overhead console-thermometer problem. If someone reads this, has a service manual and can tell me where the thermometer draws its power it would be greatly appreciated. I've got some manuals located but I've been unable to stay in one place long enough to have them shipped lately.

Thanks

camelracer

sjester
The following pinouts for the overhead console connector are from an '96 manual but it's probably the same as yours.

1 - fused panel lamps (dimmer switch)
2 - park lamp switch
3 - n/a
4 - temp sensor ground
5 - temp sensor signal
6 - courtesy lamp driver
7 - ignition switch (start/run)
8 - n/a
9 - ground
10 - n/a
11 - ground
12 - fused battery
13 - fused battery

sjester

Thanks Camelracer! I finally resolved this issue yesterday. A problem developed with my transmission temp gauge so I checked all the connections and found a loose one. When I restarted the truck to check the gauge, the gauge was fixed as well as the temp gauge. I guess the PO had tapped the power for the signal amplifier into power for the overhead and the loose connection was causing the "SC" condition.