bobem12

Hello, all of the sudden the 4x4 in my '01 2500 4x4 quit working and the a/c vents don't work, only defrost no matter what setting you put the **** on. I've heard that both can be vacuum line problems, what do yall think? Please help I'm new to these trucks! I don't know what to really look for with the lines or where they run under the truck.

More info... I had to put a new vp on this truck I just bought and before it was fixed my brother and dad decided to tow it down the driveway and when they turned evidently they ripped out my fog light wiring and the broke a tranny oil line. Tranny line is fixed and I'm workin on the fog lights but could the problems with the vents and 4x4 be traced to this? The 4x4 and vents both worked perfect when I bought the truck, 2 days later vp died, then they towed it, then I get it back running but with no 4x4 or vents! Its always somethin'!!!!!!!!!!!

babyjoe

I would bet they unplugged a vaccum line on the firewall behind the cylinder head, both are vaccum operated, no doubt thats what it is...

nickg

The line right at the vacuum pump I'll bet is unplugged, its right at the elbow on top of the pump, if they were working near the VP I'll bet it got knocked off...I've done it a couple of times on mine

AggieJustin

Yeah, mostly likely the main vacuum line if they had worked around the VP44. Otherwise, trace through the system and look for any opening.

Had a friend's '99 where the line fell on the exhaust housing and melted through. Once you have an opening, you lose all vacuum.

MATTIEBOB

sounds like a vacuum problem to me. check the vacuum with a gauge at each tee, starting at the vacuum pump and work your way across the firewall and check the 4wd switch on the front axle the vacuum lines there are known for going bad or getting pulled loose.

bobem12

thanks guys. Gonna try to get to it tomorrow and see what I can find

mrclean

Another place to look....under the driver-side battery at the cruise control servo. Battery acid drips down on the plastic vac tube. Easily missed unless you know to look there.

bobem12

Well I got 'er fixed up! Was the vacuum line from the pump to one of the t fittings up by the firewall. A\C is blowing cold out of the vents and the 4x4 is working great. Thanks guys! This is a great site!

markman

You guys are a life saver! I was all set to take my 3500 in to an AC shop as I was having the same issue. After reading this , I went out and found a broken vac line. After replacing it I now have an AC again and at 100+ degrees thats important. Thanks again to you for the info.