Join the Car Talk Community!

Discussion Rules

Welcome to the Car Talk Community!

Want to ask a question or join the discussion? Great! Join now.

Sign In Register

1997 CHEVY 4WD PICKUP WONT GO INTO 4WD!!!

I HAVE SHIFT ON THE FLY 4WD IN MY 1997 PU. THE 4HI SHIFTER JUST FLASHES WHEN PUSHED AND WONT GO INTO 4 HI 4WD.WHAT TECHNIQUES DO I USE TO TROUBLE SHOOT AND REPAIR THIS PROBLEM!!!
Tagged:

Comments

  • edited February 2011
    Autotrac (Auto 4wd) or Controltrac? Is the transfer case engaging and/or the front hubs?

    According to a GM tech I know, if 4wd is not engaged on a regular basis the Transfer Case Control Module (TCCM) will lock up. To reboot the TCCM, disconnect the wiring harness at the TCCM or disconnect the battery.

    Next check the vacuum lines, I found a few rotten ones on my 2000 Blazer last year. When the 4wd quit completely on the Blazer it turned out to be the vacuum switch that controls the vacuum actuator that engages the front axles. Scroll about 1/3 of the way down the link to see the switch.

    http://www.automotiveforums.com/vbulletin/t572914.html

    Here's another useful link

    http://www.kylestubbins.com/node/11

    Good luck and please turn off the caps,

    Ed B.
This discussion has been closed.