2000 jimmy, no 4x4 switch lights or 4x4

[kenman1717]

i have a buddies 2000 jimmy. i just did the intake gaskets, afterward while i was running it to bleed the air from the cooling system i noticed it had no 4x4 lights on the switch, nothing happend when you pushed a button. its only a 3 button switch, 2, 4hi and 4lo. 4x4 did work before the job, i used it so the front tires would pull the truck onto the ramps. the battery out on the bench for a week while i did some other stuff to the lights.

i'm a licensed auto tech so have done a few 4x4 inops on blazers, but they always had lights on the switch and the buttons would always do something if pushed, was usually a vacuum line or the tccm.

made sure my vacuum lines were good under the hood, nothing pinched or unplugged. there is power to both sides of the 4x4 fuse and the atc fuse.

there is no bulb check on the switch when the key is turned on, have tried jumping pin 13 but nothing happens. checked the tccm just for the sake of it cause its a known common problem, one terminal was a little green on the connector but that was it, nothing green on the module, so cleaned the connector and put dielectric grease in there.

popped the switch out of the dash and unplugged it, nothing obvious. have pulled the fuses and put them back in, didn't do anything.

any help would be appreciated, a wiring diagram from the fuses to the switch would be good, i would like to know if the wire comes right from one of the fuses to the switch or does it go to the tccm first.

i really think this problem has to be coincidence. have talked to a few other techs, and no ones has had a problem like this after an intake job.

[kenman1717]

just a bit more info. i have driven it. it is in 2wd so that part is working. there is no service 4x4 light.

i did find a wiring diagram for the switch, tested for power on the brown wire coming from the 4x4 fuse, test light lit up, so there is power coming to the switch.

unable to post diagram, its to big. it shows 3 power inputs, one from switch, one from bcm, and one for interior lighting. test light lit on all 3 wires. going to try another switch from another vehicle to see if anything happens before i spend $150 on a new switch.

[kenman1717]

update:
so i got another switch, when i turned the key on the lights blinked on the switch but none stayed on, of course when i tried to start the truck the battery was dead. boosted, backed it out and tried the 4x4, still nothing.

was told today about the possibilty of a single wire that runs behind the intake for the 4x4 that is some times a problem, but normally on the full size trucks from like 96-98 that had the vortec engines, have no confirmation on this wire on the blazer or jimmy. checked behind there couldn't see any single wires.

am really at a complete loss here, checked the wiring diagram again for the switch, could only find one ground and it was shared with the back lighting on the switch, which is working. i think it grounds in the tccm, but not hundred percent.