Hey
I found this forum and it is really cool.
I have a 94 blazer s-10 tahoe 4 door/4wd with about 100k.
The truck is used mostly on weekends about three to six times a month.
It has afew bugs in it but it still is a great truck.
Yesterday I noticed the truck's ac would switch to defrost and your feetas you acclerated, and then comes back through the vents as you cruised down the street.
Plus the odometer just stopped working. The speedo still works (not digtial).
Any help would be great.
Thank you for providing a great reference site.
Greenbean

 

On the a/c it sounds like you have a vacuum leak from the motor to the a/c blower head, check on that, also on the odometer issue does the numbers change? if not it could be the motor, or the board that controls the numbers.

 

thanks for the suggestions