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trainwreck · 10-19-2011, 11:37 AM

I have a 2001 Georgie Boy Landau on a workhorse chassis. When I am traveling and using the dash air conditioning it works perfectly until a load is applied to the engine. For example as you start up a hill the dash air just quits working. The air blower stops completely. When you get on the other side of the hill and let up on the gas it starts working again. Anyone got any ideas.
Thanx

Perry White · 10-19-2011, 11:41 AM

loosing the vaccumn. That's normal.

GMRHost · 10-19-2011, 11:49 AM

I do not know about your specific situation, but I know of a couple possibilities;
One could be that there is an AC cutout that was either factory installed or aftermarket for fuel conservation ... guess that leads to the question, has it always done this?

Second- and this is from my Superduty, not workhorse, experience; The diesel SDs have a vacuum pump that operates all of the "doors" in the cab air system- if it fails, it defaults to defrost (but you said the blower stops, so that must not be it)

Hope this was more than totally useless... also, we do have a "Workhorse" subforum that you might look up and post there... just a thought

ocn · 10-19-2011, 04:19 PM

just had a similar issue with my 2010 Workhorse chassis RV. Dash a/c appeared to have stopped working but it had defaulted to the defrost mode. The vacuum line to a vacuum canister on the upper left in the engine bay had come off. Put the line back on and problem solved. If this is a new problem, then a vac leak is a good bet

redtop · 10-20-2011, 03:54 PM

I have a very similar problem on my MH, Ford 460 gaser. whem I'm on a hard pull the AC cuts out ,the fan slows down and warm air comes out. it's
a real pain. i did talk to my mechanic about it he siad he would look at it
but at $60.00 a hour I'm hopeing someone has a real answer. I have a 1998 airbus with only 38,000 miles on it.

ocn · 10-21-2011, 10:06 AM

If you don't have a vacuum tank in the system it probably isn't holding the vents open on long wide open throttle runs. Adding a tank isn't hard and you could probably find one in a bone yard off a car or truck. Many turbo powered vehicle use them.

If it is a new problem, then a leak has developed someplace in the system.

doc · 10-21-2011, 10:34 AM

Don't know about MH, but that was a standard on one of the many cars I have had over the years. A PIA also!

ga traveler · 10-21-2011, 05:58 PM

The next time it happens, have someone feel at the windshield defrost outlets. You will find the air is coming out here. This is a safety feature. It is to insure that if you lose all vacuum, your windshield will stay defrosted. Your system has a vacuum tank. start checking here. there will be the large supply line and a small outlet line. The large one is a common problem area. it splits at the end. Also check the tank. It is plastic and many times cracks. If both of these are OK check all vacuum lines for splits.