My vents don't work, no mkatter what setting it's on, it blows out the defroster. Also, my front axle isn't engaging.
The vacumn lines to the front axle were replaced by the dealer as a courtesey, while they installes a new ABS system. They said that my 4x4 should work now, but it doesn't.
How would I test the vacumn pump? My brakes are hydroboost, so they're not affected.

 

Your vacuum pump is right under the VP44 and in front of the power steering pump. They don't typically go bad though... and for around $2000 + core they shouldn't!

I would check for vacuum leaks first.

 

...check just under the center of the cowl, there is a vacuum tee there...I've had two leaks, both were sourced to connections falling off of that tee.

 

Vacuum pumps can be had for way less the $2000 if that's your problem.

 

Do you have cruise control? If so did it used to work and now doesn't? I broke the line going from pump to firewall while changing fuel filter. I got a vacuum line cap and cut the end off, made a perfect splice...gl

 

My cruise Control works fine. So, I guess I need to start tracing vacumn lines.