Intermittant A/C problem

[Max Tunnell]

A new situationas of today.

The A/C will either stop working or turn itself to a warmer setting and/or turn the fan down (or somwtimes off).

This happend several times today. It always comes back on or returns to the right settings after 1 to 4 minutes. It seems to come back sooner if I slow down or start down a hill. It will have the problem again going up a hill or at 65 to 70 MPH

Ambient temp about 93 to 96. No TOAD today.

I would guess there is something happening with changes in engine temp, load or throttle setting. There is no indication of overheating or runnong hotter than usual. Coolant is not low, but i will recheck in the morning when it is cool.

It does not have a problem at 55 or slower.

It this a malfunction of the A/C or is the A/C responding to the above mentioned engine conditions

My signature should show my coach as a twin of Driver's

[Max Tunnell]

A new situationas of today.

The A/C will either stop working or turn itself to a warmer setting and/or turn the fan down (or somwtimes off).

This happend several times today. It always comes back on or returns to the right settings after 1 to 4 minutes. It seems to come back sooner if I slow down or start down a hill. It will have the problem again going up a hill or at 65 to 70 MPH

Ambient temp about 93 to 96. No TOAD today.

I would guess there is something happening with changes in engine temp, load or throttle setting. There is no indication of overheating or runnong hotter than usual. Coolant is not low, but i will recheck in the morning when it is cool.

It does not have a problem at 55 or slower.

It this a malfunction of the A/C or is the A/C responding to the above mentioned engine conditions

My signature should show my coach as a twin of Driver's

[John_Canfield]

Assume you are talking about dash air...

My first thought is a problem with the compressor (clutch slipping, clutch being disengaged, belt slipping) which would make the air warmer but that wouldn't explain the change in fan speed.

[bill jones]

I think you may have a problem with your vacuum system. A good indication is when you place the engine under heavy load your vacuum will decrease and the various heat/AC settings will change with the availability of vacuum. Conversely the A/C will come back when you head down hill because the vacuum returns to normal. Could be a slight leak. All your heat/AC and defrost settings are controlled by vacuum actuated dampers and flaps. BTW the default setting (no vacuum) is defrost, check and see if this is where your air is blowing when this malfunction occurs.

On my last rig (ford chassis) there was an inherent problem with enough vacuum. Fix was an extra vacuum reservoir.

[Max Tunnell]

bill j,

That sounds right. I, too, has a Ford chassis at one time and that is exactly what happened. It was hard to fix, too. I had hoped the WH was immune, but I guess not.

I hope the WH is not so difficult to fix.

[bill jones]

You have lots of company on that problem Max, I have a slight leak in my vacuum system on this rig, I know where it isn't, just not where it is. DP's have a much simpler vacuum system, but I still haven't fixed this one.

Good Luck.