poor a/c on '05 when at low speed / stop

[formula]

What's happening is that when at a stop or traveling at low speed, the fan clutch doesn't speed up the fan when the a/c is on. This causes the compressor to kick off and on because the condensor isn't being cooled. The cooling inside the cab is poor at best in this situation. I've sat and listened to or watched the fan on a few occasions, like today, to see what it does. The fan will run at slow speed, like barely 200 rpm, for a good minute or two, then it speeds up for about 15 seconds. If I'm inside the cab I can tell when the fan is coming on/off because the air temp will drop and then go back up again. Coolant temp doesn't seem to have any effect on this behaviour. I've read about a similar situation on the '03s, but not on '05s Maybe there's a TSB?



Sean

 

[EB]

It is your fan clutch. If you have an 05 I would insist that they change the fan clutch. I've had that problem twice, and a new fan clutch solved it. Needless to say I wasn't under warranty.

 

[BHolm]

Mine is the same way and I am also not real pleased with the AC performance. I can't figure out why they went to an eletrically switched fan on the third gens. What was wrong with the old thermo clutch variety? I lost a transmission to a failed electric fan clutch on one of my '03's. Never thought to consider the fan in my poor AC situation. Thanks for the heads up!

 

[rashwor]

My '92, 99, and 05 all have this issue. If you use the recirculate air position on the control instead of outside are, all is good. Just my thought. My fan clutch seems to be working fine on the '05.

 

[formula]

Mine exhibits the same behaviour no matter what position the control is on..... recirculate, outside air, defrost, etc.



Yes, I turned on the a/c with the snowflake button and the heat control is all the way on cold :-laf



Sean

 

[67guzzler]

Sean -- I know it's obvious, but in addition to the fan clutch, I'd ask the dealer to test the refrigerant level. The compressor can kick off at inopportune times or have odd cycles at low speeds if the refrigerant level is barely adequate / inadequate. If it's low they should recharge the system to spec and then do a dye test to see if they can find any leaks.

 

[formula]

Well, it's going in to the dealer on Monday to see if they can get this sorted. I'll be sure to ask about the refrigerant level as well.



Sean

 

[EB]

You might ck and see if you have a P-480 or P-483 code. They indicate a problem with the cooling fan. Mine showed one of them, I believe it was the 483 code, low fan speed. Mine is an 03, codes might be different on different yr models.

 

[MLimpert]

Mine is the same way. I use the high idle feature if I am parked for an extended period of time, and that seems to help a bit. The A/C will freeze me out of the truck if I'm rolling though.



Maybe you should convert it to R12. That would do the trick. :-laf