99 1500 Silverado xcab 5.3vortec w/autotrac
Does not engage 4x when I push the buttons. The amber led on the 2wd
is faded most of the time and other times is normal brightness. Many
times the led on the 2wd button does not even light.
When I push any selection the amber led will flash on/off on that
selection with no transfer case engagement and then revert back to the
Where can I start?
say that it is your issue but I have replaced many. There has also
been issues with the encoder motors on the transfer case as well as
TCCM modules themselves. Try borrowing a switch from someone else's
truck. The dash face just pops off and the switch easily pops out.
There will also be a code stored in the TCCM if you know someone to
First place to start would be to see if there are
any relevant codes. When the light flashes on/off
and then reverts back to 2WD....it's telling you that
it has attempted to shift but for whatever reason
cannot finish the shift. It might be that the encoder
motor physically is not able to shift the t/case, it might
be that the front axle is not engaging (though you usually
see the 4WD light flash continuously and not revert
back to the 2WD position).
Unfortunately...it makes diagnosis so much easier
on these vehicles if you have a scan tool.
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