Gmc stuck in 4wd

#1
Got a 99 1500 sierra and the damn thing is stuck in 4HI. I think its an electrical problem cause sometimes it works sometimes it doesn't. normally I dont care cause it get stuck in 2wd but we put in in 4 and now we have to drive around town like that and its damn annoying making sharp turns. Its mostly a farm vehicle so its not driven daily. any help/suggestions are appreciated.
 
#3
Taking the fuse out resets the tcase shift actuator. Another thing to try is the ground strap on the body mount under the drivers footwell. It is for the tcase and is known to lose contact. Are the dash lights on the button on? Service 4x4 light? Try the fuse and or the ground strap first.
 
#5
i will try the fuse. jimbo the service light is on and the indicator lights work 95% of the time they go off every once in a while but never for more than a few minutes.
 
#6
If the fuse doesn't work clean the connection where that ground strap bolts to the body mount of the frame. If neither do it it could be the shift computer in the dash behind the 4wd buttons. On my 01 chevy I had to replace the buttons, tcase motor, and the shift computer.
 

LBarr2002

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#7
If its the same as mine ('01) there have been issues with the solder connections in the switch (dial on the dash). Mine is starting to go out and tells me to service 4wd system every once in a while.
 
#8
If its defaulting to 4wd its rarely the button. Usually a ground issue, the shift computer going bad or the decoder motor on the case. Life would be alot easier if no one had decided the lever was such an" inconvienece"
 
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