A/C trouble

[Gary DiPietroSr]

Anyone else had a problem with their A/C? Mine is intermittant. When going uphill with the engine reved and the speed rising, the air just stopped coming out the vents, but I could still hear the fan blowing. I let up on the gas and it started working. It did this twice today. It stopped working a few weeks back but been ok until today. Any ideas? Thanks, Gary D. in CT

 

[Bill Ellis]

Might be normal; some vehicles turn off compressor when engine load gets high. Don't know if the Trac does this though. Maybe someone else can verify or tell us it ain't so.

 

[Gavin Allan]

You have a bad check valve in a vacuum line.

 

[Todd Z]

You either have a bad check valve in the system or you used up the stored vacuum to the dash pots and they shut down...

This is normal on WOT and hard accell...

Todd Z

 

[Gary DiPietroSr]

Thanks, I'll get it to service. WOT??? Todd, having a L.I. meet?? Gary

 

[Dre L]

Gary, look for a loose vacuum hose under the glove box, or near the air filter box but under the intake tube

 

[VJ Bolton]

If it's continuing to blow - but not staying cold, your overall cooling system (radiator) may be having problems. E.g. stuck thermostat etc. Mine did that a few weeks ago.

 

[EddieS'04]

I agree with the others about the vaccum checkvalve or leak. Other cars of mine have done the same thing. That was my fix.

 

[Richard L]

If your AC vents stop blowing out any air when accelerating or pulling a long hill, you probably have a vaccum leak. Engine vaccum is lower when the throttle is opened more (Under load) and if there is a vaccum leak, there may not be enough vaccum to keep the AC

(vaccum controlled) air flow doors open. The vaccum leak can be anywhere in the engine compartment or under the dashboard Heater/AC controls.



...Rich

 

[Mike Wilson]

I think I can help on this one. The a/c will shut down the compressor on acceleration/throttle inputs of over 80% on G.M. cars, not sure of the percentage on Fords yet, but this is designed into the p.c.m.(powertrain control module) to assist in heavy acceleration or high engine loads to help the engine out with H.P.Have noticed this on my ST.

 

[Gary DiPietroSr]

Thank you all for all the input. I'll let you know the turn out. Gary D. in CT

 

[Kevin Palmer]

Unless they have changed the system as I know it I say it is doing what it is suppose to. With the old model carbs and early injection system there was a switch that was pushed at WOT that disabled the A/C compressor. This is done electronically now via the TPS, (Throttle Position Sensor). At WOT the ECM turns of the relay to the compressor to allow full engine performance to the tires. It should only happen under heavy load or when in passing gear for example.

 

[Richard L]

I agree that if the AC is blowing hot air on WOT acceleration or when pulling a long hill, that the AC compressor clutch may be designed to shut off at WOT.



But what I'm hearing Gary D. say is that his blower is running, but NO AIR is coming out of the AC vents. That sounds like a vaccum leak and the low vaccum created with the throttle wide open coupled with the leak is causing the doors to the AC vents to close and NO AIR is being sent out the AC Vents.



Shutting off the AC Compressor Clutch would still allow the system to blow air out the AC vents. it would just be Hot Air because refrigerant is not circulating through the evaporator core.



...Rich

 

[TRACket Paul]

I have a similar problem that started recently. With the A/C running, in either position (std or max), the air sometimes loses its coolness. Fan speeds are not affected. It occurs at idle and when cruising. Turning it to the Vent position then back to A/C sometimes fixes it.

 

[Kevin Palmer]

Ohhhh, I see what your trying to say Rich. And I agree.



If there is air flow then I would think it is like I described above. If no air flow comes out of the vents then I agree with Richard that you have a vacuum hose issue...