Reinstalled dash; no 4x4 buttons illuminated

[dlundblad]

Happy Friday BITOG. (I posted this on the S10 forum with no luck..)

TL;DR I reinstalled the dash and the 4x4 switch isn't illuminated and 4WD won't engage.

More info: I removed my dash to fix the air out of defrost/ feet only as well as replace the heater core. I also replaced the faulty t case vacuum switch, 4x4 vacuum actuator and all hoses in between. Everything is back together and my 4x4 buttons do not light up and the 4 wheel drive doesn't engage. I am assuming even if the vacuum was wrong, the button would still light up?


Thankfully, the snow isn't flying just yet!

 

[Smoky14]

Fuse??

 

[mk378]

Did you disconnect the battery during the process? Unplugging/replugging stuff with the battery connected is prone to blow fuses and modules.

 

[Trav]

Sounds electrical to me, check for power and ground, loose connections, fuse, etc. Do you have a power probe? Its the perfect tool for this job.

 

[dlundblad]

The fuse is fine. I even swapped it with another. No change. The battery was disconnected for the job.

I don't have a power probe. I do have a volt/ multi meter, but I wouldn't have the slightest idea on trouble shooting. The plug that comes out of the dash and plugs into the switch has 5 prongs.

 

[CT8]

What did you do wrong? Years ago on my wifes 7.3 Power Stroke I changed a fuel hose to the cyl head and a few weeks later a miss developed . A neighbor that was a "tech" looked at it said you need an new injector? I pondered about about before the miss? Duh I changed the hose to that cyl head where the miss was. I replace the hose and the miss went away. Again what did you do wrong It worked before you did the work.?

 

[andyd]

In 50 odd yrs of trying to fix stuff, I think I have encountered maybe 2 coincidental failures. If something doesn't work after I've been fixing in the area, at least I know where to start looking. Can your S 10 guys point you toward a pdf of the wiring diagram?

 

[dlundblad]

Originally Posted By: andyd
In 50 odd yrs of trying to fix stuff, I think I have encountered maybe 2 coincidental failures. If something doesn't work after I've been fixing in the area, at least I know where to start looking. Can your S 10 guys point you toward a pdf of the wiring diagram?


I'm guessing it's either a $20 part or a $180 part. Aside from shooting from the hip (and tearing the dash out again), I'm out of ideas.. and was just hoping someone would have previous experience.

Car specific forums are nice to have around, but BITOG is more well rounded IMO. Thanks anyways. Have a good weekend.

 

[Trav]

Did you figure it out or do you need a wiring diagram?

 

[andyd]

Originally Posted By: andyd
In 50 odd yrs of trying to fix stuff, I think I have encountered maybe 2 coincidental failures. If something doesn't work after I've been fixing in the area, at least I know where to start looking. Can your S 10 guys point you toward a pdf of the wiring diagram?


"I'm guessing it's either a $20 part or a $180 part. " OK. Me, I guessing it is a loose or strained connection. My reasoning is that if it worked before you opened up the dash and now it doesn't. It is unlikely to be a part

 

[dlundblad]

Originally Posted By: Trav
Did you figure it out or do you need a wiring diagram?


I have a FSM that I am sure has it.

Haven’t had a chance to work on it yet, but thanks for asking.

 

[Trav]

First thing to do is establish power and ground are present at the switch, just put VOM to 20V DC probe the red wire to the + wire on the switch and the black to a metal ground it should have approx 12v.
You can test grounds by first identifying the ground wire from the diagram then switch the VOM to low ohms, probe the ground with one probe and put the other to a metal ground (body, chassis) and it should read close to 0.

 

[dlundblad]

The switch wasn't plugged in.. Hence why it wasn't getting power.

The switch plugs into a wire that runs through the dash to the driver side where it plugs into another harness at the firewall.

 

[Trav]

The switch is where I was going. Glad you found it, good job!