Ac compressor not coming on

[CalebKornegay]

I have a problem with the ac on my 2005 GMC Sierra. Majority of the the system including compressor, accumulator, lines, and low pressure switch. 
 

The problem is my compressor will not come on when it is called for. It has correct refrigerant charge, fuses and relays are good. Low pressure switch had 5 volts to it. Compressor is not receiving any voltage. 
 

I can take the compressor relay out and jump it out at the fuse box and the compressor will run. Had this problem on and off for the past couple weeks. I have taken the HVAC/ECAS dude out for it to reset the system and it worked but now it will not fix the problem.

 

I cannot find any videos on YouTube that helps me any and I can’t afford to take it anywhere.

 

Any advice to help me fix the problem will be greatly appreciated. Thanks.

[sefiroxx]

Any codes?

Manual or auto climate? If auto, the temp sensor may be bad.

Pull the harness from low and high pressure swItches and jumper then

[CalebKornegay]

Auto climate. It’s not throwing any codes that I’m aware of. Was throwing code for blend door the other day but I put a new one on. It kinda has a mind of its own. It will either blow ice cold one day, not too great the next and then just stop coming on over all. Do you mean jump the low and high pressure switch at the same time? And where would temp sensor be located?

[sefiroxx]

Since you blamed the pressures are good (using a full set of guages measuring go and low), then the pressure swItches should allow compressor to come on. By jumpering them, if the compressor comes on, you know one of the pressure swItches is bad.

If the compressor does not come on, then some other control mechanism is at fault.

There are two temp sensors. Interior Ambient is on the dash. There is a an exterior sensor behind the grill used to control what comes on for defrost and might be used to switch off the compressor when there is plenty of cold air outside to use (and you are using fresh air intake).