08 no heat and 4wd acting funny???

[mmoon]

Ok guys, First off I noticed my four wheel drive was acting funny the other day, flipped the switch to high 4wd, put it in neautral, eased of the brake and put it back in reverse. The front tires werent pulling so I locked the hubs and put it in low 4wd worked fine, yesterday went to go to work and theres no heat, blower motors work, controls work, defrost works, just no hot air coming out of the vents.. Today went to hook to a trailer in the field 4wd worked fine on the high side with the hubs manually locked, but still no heat? Went to the dealer no "deisel mechanic" working, talked to a deisel owner he said possibly a bad vacuum pump. Any advice or any one have this problem.

[Antonm]

I would bet you either have a bad vacuum pump or a vacuum leak. The pump is under the hood on the driver side fender. Its on top of the fuse panel thats under the hood. You should be able to hear it running when your waiting on the glow plug light to turn off prior to starting. The vacuum tank is under the driver side battery. Vacuum operates the 4X4 auto locking hub feature as well as the heater control.

[mmoon]

looks like its the vacuum pump so far, went out just now and checked it, and you cant hear it running... thanks man i appreciate it.