i have been reading several posts and cant find what im looking for.
i am working on my sisters 2002 s-10 blazer. her 4x4 switch stopped working all together and had the dash displaying service 4x4. well i pulled the tccm out and found very bad corrosion. picked up new pin connector ends and replaced the two worst on the 32 pin connector. and on the 4 wire pin connector i scrapped off the corrosion. the original tccm was bad since the corrosion ruined the male pins and one was broken off in the plug. anyway, i picked up a new tccm from the dealership and put it in. plugged the battery back up and stated the truck. the push button lights came on and blinked, the tccm cycled as you could here it than it all quit. no pushbutton action anymore.
turns out the fuse in the engine compartment blew. i changed the fuse (20 amp) and as soon as the fuse touched the termanals, it blew.
heres what else i have to do. replace all the vaccum lines as they are rotted badly.
i need help to diagnose this. i know a blowing fuse is an idication of a short. any idea where i need to start?

 

Pull the 4x4 switch out and check with multimeter ony other switch i can think of is vac switch on the transfer case.

 

so basicly, i have to test the switch. chase wires and change all the vaccum lines. i know all the vaccum lines under the hood are bad. i found one bare red wire grounding out (that i know of) between the fuse box and air cleaner which looks like an unused power wire to something. looks as if it never was used by the factory.
on a side note, i have pulled the dash out twice. once to replace the heater core and another time to replace a broken flapper door in the heater box.
i'm wondering if i pinched the main wire harness behind the dash, but i doubt it.
i'll pull the tccm back out, pull the pin connector back apart and replace more female plugs if i have to. this is going to be a pain in the .....! i'm not even sure if the transfer case control motor is even working.
and i have to chase down where the broken wire is that keeps popping the tcm 20 amp fuse in the engine compartment.

 

multimeter, jumper wires and wiring diagrams are your best friends when chasing electrical problems.

 

i've got all but the wire diagrams. can't find them no matter how hard i look. i need the diagram under the hood to the fuse block and i can figure out the 32 pin tccm harness to the switch on the dash. no big deal.

 

only thing i can think of is diy alldata site punch that into the old google machine. it cost $30-40 for a yr but well worth the money.