1999 GMC Sierra Heater fan & 4 wheel high/low shifting

1999 GMC SIERRA
162,000 MILES • V8 • 4WD • AUTOMATIC
Avatar
ROB PLANCE
  • MEMBER
  • 1 POST
The heater defrost fan motor works intermitiately.
Also it appears to quite functioning when the transmission refuses to shift into 4 wheel drive (high or low). The indicator light shows it is trying to shift but never does shift into 4 wheel. The transmission appears to function fine.
Dec 23, 2008 at 6:43 AM
Advertisement
Avatar
JEN6238
  • MEMBER
  • 9 POSTS
first, when my heater worked intermittent it was the plug into the blower motor (remove glove box) a short trip to the junkyard and I even matched the wire colors snip, snip and a little solder.
Second 4wd is usually the ENCODER MOTOR in your situ again junkyard if your inclined. Practice removal at the yard if you need to.
Jan 3, 2009 at 12:55 PM
Add a reply
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.

Ask a new question

Frequently Asked Problems for This Vehicle