95 4wd Actuator

[JonS86]

Hey guys, thought I used to be a member here years ago, but couldn't remember my login lol. Anywho, I know this will be a topic that's been beat to death already, but here we go...


I'm stumped on the 4wd system on my 1995 K1500 Auto. I've changed out the transfer case switch and actuator on the diff. It has been upgraded to the motorized version with the wire harness add-on to give it 12volt when switched. I've done my wire test with multi-meter and test light with key on. Getting power where it should be getting it, bu it's still not going into 4wd. You can feel the case turn the front drive shaft in 4lo-4hi, but the actuator is not getting any power. I've replaced everything I know of including putting in a new Dorman 600-600 actuator harness. I'm clueless and irritated lol.


What else is in the food chain to look at?

 

[andy396]

There’s a relay up in the firewall and a fuse.

I’m honestly a little confused. It’s getting power to the actuator but the actuator isn’t moving? Have you tried testing it when removed from the diff? Have you confirmed the spacer that’s part of the conversion is inside the diff?

 

[JonS86]

Yeah I've tested everything. Getting power to all parts just no luck getting it to work. The spacer is in fact in there as well. It was previously converted over to the new actuator setup, but for some reason it stopped working 4 or 5 years ago. I'm puzzled on this thing, but I also didnt know about there being a relay up there? I'll have to look at that tomorrow.

 

[JonS86]

So, I've checked for a relay on the firewall. This 95 doesn't have any that I can see. I remember my old 90 had 3 there on the passenger side under a little cover, but this truck doesn't have that. Must've had a changeover during 95. There is a black relay and fuse box on the driver side, but nothing is labeled 4wd. Where can I can find it?

On a side note, if take the actuator out and let it hang, when I shift to 4lo-4hi, it should operate correct? Unless I've bought a bad unit out of the box...like I said I've tested everything to make sure there's 12v where it should be.

 

[andy396]

So, I've checked for a relay on the firewall. This 95 doesn't have any that I can see. I remember my old 90 had 3 there on the passenger side under a little cover, but this truck doesn't have that. Must've had a changeover during 95. There is a black relay and fuse box on the driver side, but nothing is labeled 4wd. Where can I can find it?

On a side note, if take the actuator out and let it hang, when I shift to 4lo-4hi, it should operate correct? Unless I've bought a bad unit out of the box...like I said I've tested everything to make sure there's 12v where it should be.

Here you'll find complete service manuals for your truck and for a '98 truck which would have the newer style actuator. If I get a few minutes I'll look for myself, but that should be what you need to trace things out.

https://www.gmt400.com/threads/88-95-service-manuals.43575/

Yes, if you just let it hang it should actuate outside of the diff. You can also put something in the hole and push to manually engage the diff and just check that everything mechanical is working.

If the actuator is working, then you're either missing the spacer that's needed or something is broken inside your diff.

 

[JonS86]

I'll look over the manuals. I'm pretty sure the spacer is in there, but I'll double back and make sure. And I sure hope nothing is broken inside the diff... Either way I'll report back with my findings and go from there.

Thanks for your help my friend.

 

[JonS86]

Ok, so just took a short lunch break and tinkered on the Chevy. Checked for the spacer and it's there. Checked all wires again looks like everything was good. Took out the actuator and let it hang down. Put the truck in drive and switch to 4hi...nothing. Investigated a little more and decided to trace and wiggle wires boom actuator pops out. I'm guessing up top where the transfer case switch is the connector to it seems to be shorting out!!!!! Wiggled some more and the actuator goes in and out like normal, but when i don't touch it the 12v disappears. I think I'm going to just pull an upper harness from the scrap yard this weekend and replace mine. Not sure if you can buy just a connector from the parts store or not. I hate electrical gremlins lol