Noticed AC compressor cycling 2011 GMC Yukon XL Denali

[Cusser]

2011 GMC Yukon XL Denali, just purchased by us in May, 75K miles. R134a, dual AC.

I rarely drive this vehicle, but did drive it on a trip from AZ to CA in the summer. Anyway, Mrs. Cusser drives it all the time, and I noticed when she returns from somewhere that the AC compressor cycles every few seconds as she drives into the garage. The AC cools great, not sure if the driver can even notice this. Any suggestions by the experts here, like is this normal??? Thanks.

[tbirdtbird]

Cusser, would pressures help us?
Dave

[Cusser]

Cusser, would pressures help us?
Dave

Maybe, but I haven't seen the need so far to measure the low and high side pressures, maybe I'm wrong. I am of the understanding - likely incorrect - that these systems are designed so compressor is always on (not like my 1998 and 2004 Frontiers which use an evaporator-mounted thermostat switch to interrupt voltage to the compressor when the evaporator gets too cold).

The Yukon AC does great in Arizona summers, why I'm reluctant to mess with it. There's no evaporator freeze up or other MVAC issues.

All I've done since purchasing this in May is swap over the Four Seasons Deslugger from the 2005 Yukon, that is an electronic thing which only prevents full compressor engagement for the first few seconds of start-up, because oil can accumulate in the low-mounted compressor. That's a highly rated product, was MVAC product of the year too.

[Tim]

Inlet and outlet evap tubes similar in temp? If so find something else to worry about or maybe chase Mrs. Cusser around the house.

[Cusser]

Inlet and outlet evap tubes similar in temp? If so find something else to worry about or maybe chase Mrs. Cusser around the house.

Good suggestion.


And I'll check the evaporator inlet and outlet tubes too !!!

[Tim]

How do you think the price for courting the aircorn system would be?

Can you clarify this question?

[bmills2@twc.com]

bad radiator - condenser fan when auto stops moving no air is being forced through the condenser high side pressure goes to 400 psi high pressure switch turns off a/c compressor , pressure comes down compressor comes back on.
if it has a clutch fan , watch the fan and turn off motor , the fan should stop when motor stops or turn 1/4 turn good the more it free spins the worse it is any thing over 1 turn needs replaced. needs engine warm to test cold it can show good when warm be bad. when hot should lock in more ,spin less.
Electric condenser -radiator fans, both fans should come on with a/c is on. no matter what engine temperature. high side goes to 300psi turns on fans.

[Cusser]

bad radiator - condenser fan when auto stops moving no air is being forced through the condenser high side pressure goes to 400 psi high pressure switch turns off a/c compressor , pressure comes down compressor comes back on.

2011 GMC Yukon XL Denali 6.2 liter, just purchased by us in May, 75K miles. R134a, dual AC.

The 2011 GMC Yukon XL Denali has electric fans, no fan clutch or engine-driven fan (was same with our 2005 6.0 liter).

[Cusser]

I will check the electric fans next time Mrs. Cusser arrives home and I hear the compressor cycling.