Short-circuit

[nige]

Sunday afternoon I decided to do a little fishing. I launched the boat as usual, went for about an hour (couldn't be late for Father's day Tenderloin dinner) and I went to pull the boat out. I normally use 4H to get off the sandy beach, but the rear tires were spinning leaving me to believe that it was not in 4wd. So I roll back and make sure the t-case is in 4wd. As soon as I shifted it from 2H to 4H, the tach died, battery light lit up and my reverse lights were no longer working. I drove the truck to the front of the cottage, shut it down and resumed packing up the boat.

 

When I went to crank the engine over to put the boat away, it wouldn't start. I checked most of the fuses, looked at the wires going into the starter but couldn't find any problems. I was lucky I had my repair manual as it described a few symptoms of a defective inhibitor switch. This is a switch that disables the start circuit for dumbasses that try to crank the engine when automatic transmission is not in P. So I crawled under the truck and made sure the switch was properly aligned and the linkage for the gear selector was also operating properly; everything looked fine there. I then went into the electrical diagrams in the repair manual and discovered the inhibitor switch, reverse lights, meter and gauge (battery and tach), seatbelt timer and rear window defogger are all run through the same fuse. I pull the 10A fuse, obviously fried, and put another one in... truck starts fine. I parked the trailer, unhitched and drove around the cottage lanes to see if my 4wd was working or not. I noticed that everytime I switched from 2H to 4H, the same fuse would blow, even with a 15A in there. Now the little green 4wd light on the dash stays light even though the transfer case is in the 2H position, and I don't think the truck will go into 4wd.

 

I know there must be a short in that circuit that causes the fuse to blow, but my bigger concern is the health of the T-case. When you shift from 2H to 4H, is it a completely mechanical process?, or is there some electrical component that must be working properly for the T-case to do it's job? My truck is a 1995 SE with auto trans. Has anyone ever had this happen to them? Any insight is appreciated.

[88pathoffroad]

Sounds like your t-case position indicator switch (or it's wiring) shorted out on you or was otherwise damaged.

 

The transfer case operation is entirely mechanical except for the indicator light switch.

[TrailChaser]

Nooooooo, disassemble number 5.......

 

 

Sorry, I couldn't resist.

[nige]

I finally got around to testing some of the switches and wiring. All the switches on the t-case are functioning properly, so no problem there. But same thing; when the t-case lever is switched to 4WH, I get a surge of power flowing back into the fusebox (i burnt out my test-light bulb). Do you think it could be something limited to the inhibitor switch, or possibly seatbelt timers, meters & guages or 1 of the other parts connected into that fuse?

[88pathoffroad]

Try unplugging the t-case switches, shift into 4HI and see if it still does it. SOMETHING's shorting out somewhere and you gotta start eliminating possibilities.

[nige]

I found that the rear t-case switch is grounding out on the t-case as opposed to sending current to the light in the instrument panel. I think this is where my problem is, but i'm gonna cross check it with my older brother's truck (he still hasn't sold it yet...) So for now, I have unplugged the harness between the switch and the power supply so I can at least use 4wd without blowing my fuse.

Edited August 1, 2005 by skrillaguerilla