Looking for a GM code scanner.

[TURNA]

Is there a vacuum switch in that 4x4 unit?

If there is,

there is water in the vacuum hose that is freezing when it is cold not allowing the vacuum to engage the unit

It was a very common problem on the Blazers

 

[Wageslave]

Is there a vacuum switch in that 4x4 unit?

If there is,

there is water in the vacuum hose that is freezing when it is cold not allowing the vacuum to engage the unit

It was a very common problem on the Blazers

Also, those hoses break down over time and can collapse on themselves under vacuum. That or just completely dissolve in half. My blazer has that issue and EVERYTHING needs replaced.

 

[Tomeal]

Vacuum actuated 4 wheel drive..... Reminds me of my old furd truck.

Lots of parts replaced that time!