TRD_Tundra

Well my 2000 Silverado Z71 has been having AC issues lately. First started by randomly blowing air @ room temperature, now it's all the time. Can't get the compressor clutch to engage.
What I've done so far. Checked and filled Freon levels
Replaced climate control unit
Jumped the low pressure sensor
All those and the clutch still doesn't engage.
Here's the problem, I know the AC compressor is not bad because with HPTuners I can command the AC clutch to engage and it does, air blows ice cold and all perfectly.
Any input on what is causing the clutch not to engage normally?

MikeGyver

iTrader: (5)

There is a high pressure sensor up by the condenser you can check.

MikeGyver

iTrader: (5)

You Houstoners need A/C already? It's 27 here right now. Fahrenheit.

TRD_Tundra

Same method to bypass the low pressure? By jumping both wires together?

Also can the blower resistor have anything to do with this?
And if I was to replace both low and high pressure sensors would the freon leak out when I remove them?

MikeGyver

iTrader: (5)

Yep.
Nope
I am not sure if the fittings have shraders in them or not.

TRD_Tundra

Well just jumped the high pressure switch and didn't engage. Aswell as jumping both together. Could it be a bad orfice tube?

MikeGyver

iTrader: (5)

Isn't there a high pressure switch built in to the compressor on these trucks? I remember seeing one in the past couple of years, I just don't remember what vehicle.

TRD_Tundra

Bump. Checked for conductivity on both high pressure and low pressure cutoff switch's to the PCM and both are good. Replaced the orfice tube, refilled it with freon and slight oil.
I found that if I jump the relay the compressor engages. Terminal 85 has good ground on the relay.

TRD_Tundra

bump.

Suburbazine

Replace the relay (even if it works, cheap insurance), then look at replacing the AC control head (tends to fail a lot causing compressor to not get signal to engage).