2000 K2500 4WD Issue, Wiring Help

[Repstar]

I have a 2000 K2500, manual transmission with the 4x4 shifter on the floor. It has stopped shifting into 4WD and I've spent the past few days reading posts and trying to track down the issue but no luck so far. Looking for leads on what to do next. Main issue is that power isn't getting to the actuator. Power is coming out of the transfer case when I shift it into 4WD but not making it to the actuator. I'm not sure what to look for between the transfer case and the actuator as I'm having issues finding the correct wiring diagram. I *think* this might be it but not 100% sure: https://www.2carpros.com/images/question_images/12455/original.gif

Any suggestions?

 

[1998_K1500_Sub]

Does this help?

Attached, from 1998 service manual.

 

[Vanishing Point]

See if these items help your situation: Good Luck and let us know how it turns out for you. Apologies in being Dorman products.

Frequently bought together​

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Total price:$144.38
Add all three to Cart

• This item: Dorman 600-101 4WD Actuator Compatible with Select Models
  $74.99
• Dorman 600-600 4WD Actuator Wiring Harness Compatible with Select Chevrolet / GMC Models
  $47.96
• Dorman 600-502 Transfer Case Switch Compatible with Select Cadillac / Chevrolet / GMC Models
  $21.43

 

[1998_K1500_Sub]

• This item: Dorman 600-101 4WD Actuator Compatible with Select Models
  $74.99
• Dorman 600-600 4WD Actuator Wiring Harness Compatible with Select Chevrolet / GMC Models
  $47.96
• Dorman 600-502 Transfer Case Switch Compatible with Select Cadillac / Chevrolet / GMC Models
  $21.43

See also RockAuto, look here for the actuator and elsewhere for the other parts (thanks for Vanishing Point for the lead):

CHEVROLET > 2000 > K2500 PICKUP > 5.7L V8 > Drivetrain > 4WD Actuator

 

[Repstar]

Does this help?

Attached, from 1998 service manual.

Thanks @1998_K1500_Sub this is indeed super helpful!

@Vanishing Point thanks for the suggestion, switch might be good to swap out and see if that's it.

 

[Repstar]

@1998_K1500_Sub Do you know which pages of the GMT400 transfer case info.pdf you attached are applicable to a manual transmission truck with the 4WD shifter on the floor? The page titles don't seem help much but I'm guessing they have to be for different versions. Here are my best guesses starting with page 3 (the first page with a diagram):

Page 3: doesn't apply: looks like it's for a truck with the push button 4WD so not applicable for me
Page 4: not sure
Page 5: applies to my truck: fuse is labeled '4WD', not 'TCASE' and no mention of 4WD buttons
Page 6: not sure
Page 7: not sure
Page 8: doesn't apply: mentions the TCASE fuse and 'automatic 4WD' which doesn't sound like my truck
Page 9: doesn't apply: mentions 'automatic 4WD' which doesn't sound like my truck

You or anyone able to shed any light on which I should specifically be looking at?

 

[1998_K1500_Sub]

@1998_K1500_Sub Do you know which pages of the GMT400 transfer case info.pdf you attached are applicable to a manual transmission truck with the 4WD shifter on the floor?

No, I don’t, but I included all pages that appeared relevant, assuming the various combinations including yours would be covered. If anything, I think yours is called “Selectable” four wheel drive therein. Also, look mention of your transmission RPO.

I can look in the manuals again later today when I have time… happy to do so, because I learn something in the process.

You can download and peruse the manuals yourself; I’ve posted the link to them on GMT400 a few times, in random places, and can certainly provide it again

Ah! See my post here:

https://www.gmt400.com/threads/bypass-o2-sensors.56355/post-1214413

 

[Repstar]

No worries @1998_K1500_Sub, don't want to waste your time, the more I research the more I'm thinking that the 99+ GMT400s are just a bit different than the 98's and below when it comes to some of the wiring. I'm starting to think I might have to track down someone with specific knowledge on the 99+ years

 

[Repstar]

Well it snowed and the truck is at the bottom of a hill so I won't be working on it for a bit which might be good. My fall back plan if I couldn't get it sorted out was to go with the a Posi-Lok 4x4 but it seems they were made specifically to replace the thermal actuators (up to 98) so that might not be an option anymore.

 

[1998_K1500_Sub]

No worries @1998_K1500_Sub, don't want to waste your time, the more I research the more I'm thinking that the 99+ GMT400s are just a bit different than the 98's and below when it comes to some of the wiring. I'm starting to think I might have to track down someone with specific knowledge on the 99+ years

Always glad to help.

Shame the later service manual isn't available on-line like the 1998.