05 Suburban Auto 4wd Help

[Gmctodd16]

2005 Suburban 2500 6.0 4x4 have had trouble with 4wd for awhile, intermittent service 4wd light. transfer case broke so we replaced with a reman. no more service 4wd light however, 4 hi wont engage.  when 4 hi is selected the light blinks several times then switches to auto 4wd. but locks in 4wd not Auto. 4 low works as it should, Scan tool live data displays exactly what is happening. Any Ideas.

[Gmctodd16]

update: I am thinking the encoder motor is holding the TC in Auto mode. I am thinking in 2wd there should be no front prop shaft speed on sensor. Am I correct? Thinking outloud. The encoder motor is not allowing the tc in 2wd, however because the switch is in 2wd it is not engaging the front axle. Make sense?

[David89GMC]

Try replacing the switch first, it's a real failure point and only about $20.

My truck had similar symptoms, so I got a new switch and that was it.

Check out SWITCHDOCTOR on Amazon for the correct switch for your vehicle.

 

[davester]

Are you sure your transfer case has "auto"?  GMT800 2500 trucks didn't, and I would expect the burb to be the same.