K1500 4wd Electrical Issues

[97BlueK1500]

I have a 1997 K1500 and my 4wd will not work. My dash switch is good, fuses are good, and the actuator is good. My problem is I'm not getting power to the actuator. My mechanic tried to trace the wire back from the actuator to wherever it is bad, but it ran into a wiring harness with a bunch of other wires and he can't tell where it comes out. He thought about running a new wire from the actuator to the switch, but he read somewhere that this could fry my computer. He has more hours in it than he thought he would since we know the problem, but we don't know how to fix it. He has wiring diagrams, but he said they don't agree with what he's found underneath my truck. Do you have any suggestions for me to fix this and keep the push-button 4wd system, or should I just put in one of the systems that uses a cable to manually engage the front axle? Are the manual systems pretty reliable? I found one on the internet awhile back but now I can't find it again, so can you tell me a manufacturer of these? Please help me. Any ideas are appreciated.

[bill190]

Does your mechanic have *GM factory* wiring diagrams for your specific year/model vehicle?

 

Or just an aftermarket book which covers multiple years?

 

To explain the difference, I have an aftermarket book which covers multiple years of my truck and only has a few 8 1/2 x 11 pages of wiring diagrams. But I also have a GM factory electrical diagram manual for my specific truck and my specific year. This is a large 11 x 17 book with around 300 pages. All just on the my truck's various electrical systems! Everything you need to know... Everything in the specific system, connectors, switches, relays, wiring harnesses, wire colors, and locations of each thing.

 

I would suggest getting the factory manual if you know electrical wiring and want to repair this yourself. Or take your truck to a GM dealer where they will have the factory wiring diagrams for this.

 

This stuff is pretty much impossible to fix without a factory wiring diagram manual.

[97BlueK1500]

I'm pretty sure the data they have is specific to my year and model. I think they have a subscription to the AllData vehicle repair network. By the way, where did you get your factory manual? It would be handy to have.

[bill190]

...By the way, where did you get your factory manual? It would be handy to have.

 

I ordered mine from a GM dealer as part of a 4 book factory service manual set.

 

By the way, fixing this problem would be quite easy for me using my wiring diagram manual. Although I'll say I have done electrical work most of my life.

 

Anyway there are people out there for which this type of problem is quite easy to solve so long as they have the proper wiring diagrams. Other people just don't understand electrical troubleshooting. Maybe you just need to find an "electrical guru" type mechanic/person? Maybe auto/electric shop? Or GM dealer?

[bill190]

I'll tell ya what....

 

In my *92* electrical diagrams (yours *could* be different!), there is a transfer case switch as part of this circuit.

 

If you have this as part of this circuit too, then this should also be checked.

 

On my drawings, the "Transfer Case Switch" has a Brown and Light Blue wire. The brown should be 12 volts. My drawings show this switch as being on the top of the transfer case, but again mine is a 92.

 

This brown wire is the main power coming in from the 4WD fuse. But it goes through this switch first before going on to the front axle actuator.

[madhouse]

I'll tell ya what....

 

In my *92* electrical diagrams (yours *could* be different!), there is a transfer case switch as part of this circuit.

 

If you have this as part of this circuit too, then this should also be checked.

 

On my drawings, the "Transfer Case Switch" has a Brown and Light Blue wire. The brown should be 12 volts. My drawings show this switch as being on the top of the transfer case, but again mine is a 92.

 

This brown wire is the main power coming in from the 4WD fuse. But it goes through this switch first before going on to the front axle actuator.

 

Sorry for resurrecting an old post but I have the exact same problem with my '92 GMC truck and was hoping to hear the rest of the story?