Long story short: I shorted some of the thick brown wires coming out of the Satellite Fuse Box 1 (anti-theft, ecu). Relevant fuses seem fine. Clock, dome lights, electric seats, and remote locks still function. Key in pos. 2 gives nothing from the instrument panel.

Longer story: I was trying to trace my driver door switch wire from the fuse box to solve my dome light/no rear wiper issue. I found it and was trying to test it when I noticed sparks coming from behind the fuse box. Disconnected the battery and saw that a splice involving a bunch of the thick brown wires from Sat Fuse box 1 was not insulated. The anti-theft and ECU fuses are not blown. I have no sounds and no lights from the instrument cluster and no cranking.

What have I done?

 

Did you check the fuse box in the engine bay? I shorted a wire that knocked out the ignition fuse up front, with similar issues.

 

A. Dome light / rear wiper is most likely the multifunction unit, which is a box on the back of the fuse panel under the dash.

B. You have probably blown a fuse link. They look like bolted in fuses in the underhood box, and they drive groups of fuses downstream. You can read across them with an ohm meter. May work better if you disconnect one battery wire while doing hese tests.

 

Yeah, I know the MFU controls all that. However, my drivers door switch had no wire attached to it, and I had to try and find that first. Which I did. Thats the one good thing that had come out of this.

I checked the Ignition Circuit link this morning. It looks ok, but the right side looked a little dark. I will hit it with the multimeter after work and report.

 

For others who will find this thread in the future -

the MFU contols lots of simple timing issues. The dome lights are controlled and dimmed by large transistor in the top left corner. While that package is rated for 55 watts on a good heat sink, in free air it is about one watt. Two dome lights and a cargo light are beyond that, so eventually the transistor fails. I would suppose a replacement could be had from Radio Scrap or a supply house. If replacing I would add some heat sink. I snagged a used MFU from the boneyard, it is on the back of the fuse panel under the dash.

I also upgraded my dome and cargo lights to LED, so power drain is way down and brightness is better.

The under hood fuse box has conventional fuses and fuse links (bolt in high amp fuses). Many of the fuse links are like a "sub panel" ahead of more fuses. Some ohm meters are "fooled" by reading a "live" circuit, an open fuse with power and load applied will display 12 volt DC across it. Those two cables at the front should be clean and tight, they deal with alternator power to truck and charging current to battery.

 

Update:

All fuses check out. When I turn key past pos. 2 it sounds like there is a relay or 2 clicking somewhere, but no other signs of power going anywhere.

Working
Headlights
Dome light
Cig lighter
Radio
Remote locks
Clock

NOT Working
Instrument cluster
Starter
Windows
Wipers
Windshield washers
All Dash buttons
Side Blinkers
Heater/AC fan

Does this sound like I fried something weird/bad?

 

This is what shorted.

The circled section of brown wires with the liquid tape was exposed. It was crimped together and the tape for insulation slid up a good 1/4".




The brown wires lead to satellite fuse box 1. The red is described as Rear Air (dont have) and Heater, while the yellow doubles for Anti-theft Alarm and Headlight washers (removed).



If I fried something alarm related, would it kill all the stuff currently not working?

 

Be sure to check fuse link MF 5 under hood. It is upstream from the starter relay and the relay that enables the heat / AC fan.

 

You need to check to see if you have any power at all at the Fascia fuse box. Identify which fuses have power and let us know.

We can work back from there.

 

I just realized that, to test the fuses while installed, I should have been checking for voltage across the fuses rather than ohms.

Will do.

How exactly should I do that?