1997 lever 4x4 k3500 4wd wiring schematic

[seedcleaner]

Hi all. Looking for 1997 k3500 automatic with floor lever transfer case schematic. I am blowing 4x4 fuse even with actuator unhooked. I have replaced transfer case switch already. It won't blow fuse with the 4x4 relay unhooked under the hood.

On a side note, this appears to have a red wire going to a "transfer case synchronizer" from the relay. Can someone explain what that is and where? I have some schematics but not for this exact year/model.

Also, have an identical 1996 truck but only has 4 wires going to underhood relay....?

 

[seedcleaner]

Doing a little homework...my truck relay under the hood for 4x4 is wired just like this GM diagram. Nothing online I find shows the ground to be placed in this position. This has me thinking the truck relay is wired wrong........?

 

[xXxPARAGONxXx]

My understanding is that GM/Chevrolet pre-1998 (4WD) had a thermal actuator installed from the factory. An electric actuator could later be retrofitted, but it involved retrofitting the wiring harness as well.

Google "Chevrolet GM 4WD actuator thermo electric wiring." This PDF I found online may also be beneficial.

 

[seedcleaner]

Thank you...I'll look into it. I had assumed this 1997 was new enough that it originally came with the better actuator from the factory. Maybe someone wired this relay incorrectly? Because the way I understand it, this relay is shorted to ground, based on the schematic, and the way my truck is wired at the relay.

 

[packer0440]

The transfer case synchronizer (and relay) are only on one tons with a borg warner Tcase; I think it is on the back of the transfer case near the driveshaft (one wire only). I have no idea why it is actually necessary but I assume 4wd won't work correctly without it

 

[Schurkey]

Perhaps a moderator will move this from the "ENGINE" section to Transfer Cases or (maybe) Audio + Electronics.

My '97 K2500 had the newer-style actuator on it when I bought the thing...but it may have been updated by a prior owner. Based on the overall condition of the vehicle, I'm guessing it's original.

 

[seedcleaner]

Yeah, I didn't really know or find a perfect section to put this....it was under the hood technically....

This 97 doesn't "appear" to have had the updated wiring installed, it looks more original to me, but used. The wiring going to the relay looks original, but based on how a relay works, I can not see this working at all, as ground (87a) is connected to the power terminal (30). It is no wonder the fuse blows immediately.

I would love for someone with a k3500 1997ish show me their underhood transfercase relay wires. This one has five wires going to it, and almost every schematic I find shows 4.

 

[b454rat]

The 99 I parted is a K3500, has that wire coming from the t-case, had no clue what it was for. Not much left of the truck, but I can try to see where it goes.

 

[caw_86]

Best i could find, from a 98 service manual

 

[Scottm]

I came to this section hoping to find a t-case wiring diagram, and you guys delivered. Thanks paragon! I have a 97 k3500 4l80 getting a new engine, 0411 ecm, and a bunch of rewiring. Before I pulled the old engine, I was getting 4wd electrical gremlins too. The way the syncro relay originally hung from the firewall, and the t-case and trans wiring in general, is just inexplicably bad. My problem turned out to be the t-case/axle wiring was burned from going right past the exhaust manifold on the way to the front axle. I'm relocating the syncro relay to a small panel I welded onto the pcm bracket. The new wiring will go along the front cross member to the front axle, safe from the exhaust. After that pic was taken, the 4wd relay ended up all the way to the right on that new panel, which made room for an upgraded fuel pump relay and a new electric rad fan relay. I just can't get over how bad the wiring is. That sickening rat's nest in the third pic is the original trans wiring. Last pic shows how I have put on new pigtails and rebundled the trans wiring according to the connector. Why is that one harness two feet too long? And why can't they lay it out cleanly? It would cost less, have fewer problems, be easier for their own service guys to repair, and make trans service easier. Is the wiring on later model trucks any better?