Electric 4x4 insanity

[DieselDetroit]

hey guys. I could use some help with this electric 4x4 issue I'm having.

1997 Tahoe 5700

When switching into 4x4, The push button 4x4 blinks a few times, for both 4hi and lo and doesn't work, just goes back to 2hi

I took the front actuator out and put 12v to it and it worked so I know it isn't the culprit. I have a spare non-thermal actuator but it is the 5 pin style and I can't figure out the wiring.

I jumped pin 13 on the dlc to a ground and the transfer case control module (tccm) is spitting out a code 1. I've seen a few videos and all 3 lights should blink while presenting the code, but only one light (2hi) is blinking and it's very faint.

Anyways, any advice is appreciated. My understanding is that there is a transfer case relay somewhere that may have crapped out?

Anyone know how to diagnose code 1?

I tried revving the vehicle up to 2000rpm while shifting to see if it was vacuum related and still nothing. Unplugged the battery for 5 mins to see if resetting would help and nothing.

Thanks

 

[Spack9]

Had a similar issue but mine was the front actuator. Mine is the non thermal type. I would check to make sure the front actuator is getting power before going further. My harness looked pretty rough when I changed the actuator. Turn the key all the way on without starting the engine in neutral and listen to see if the transfer case is engaging. My truck gives a very distinct click when the t-case engages. Good luck.

Edit: The light will blink even if the T-case engages

 

[DieselDetroit]

Transfer case isn't engaging. The only click I hear is for the relay I believe.

Where does the signal go after the button? Is it straight to the Tccm or is there another sensor/switch that sends a signal to the front actuator? I don't have a voltmeter handy but I will double check just to be sure. The bench test checked out OK but you never know

EDIT: I attempted rotating the front driveshaft while the button was being pressed and there was no resistance. The driveshaft was easily rotated by hand. Transfer case is not engaging.