4WD Problem

[2001-2500HD]

Its a 2001 2500HD with 1 8.1L & Allison. It has the floor shifter, not the push button 4wd.

 

When I put it in 4-hi, the transfer case engages but the axels dont lock in...4-lo works fine. The 4wd light does not come on when in 4-hi and it does when in 4-lo.

Any ideas ?

 

Thanks, Artie

[GM-Tech]

Sounds like the front axle actuator has power and is working, otherwise it wouldn't matter whether it was 4HI or 4LO. There's only a single switch in the transfer case to supply a ground to that actuator when you put in 4WD. Not sure why it would work in 4LO but not 4HI.

[2001-2500HD]

Sounds like the front axle actuator has power and is working, otherwise it wouldn't matter whether it was 4HI or 4LO.  There's only a single switch in the transfer case to supply a ground to that actuator when you put in 4WD.  Not sure why it would work in 4LO but not 4HI.

 

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I know...I thought it was weird...I even put a new actuator on it and no dice... Any way I can get a wiring diagram for the actuator ? Is there a way to hot wire it or put my own switch on it ?

 

Thanks, Artie

[2001-2500HD]

I did some poking around tonight and found it was a bad ground...All is good now..

 

Artie