06 Buick lucerne. cycle switch

[Whitenight51]

A/C fully charged but compressor not kicking allways. My question is I cant locate low pressure switch, is the cycle switch and low pressure switch the same on a 06 Buick lucerne . Or is the low pressure switch in the compressor? Thanx Rick

[Cornbinder89]

No pressure switch anywhere I can see, there is a pressure transducer that sends a pressure readings to the control (ecm?) that controls the clutch. DO NOT jump pressure transducers, they are not a switch but a signal generating device, like a MAF or MAP. not off and on.

[Whitenight51]

So what I am thinking my high pressure switch is a transducer ?????? Little backround info. Just put in a evaporator. System wasn't wanting to cycle correctly before . And still doesnt. But when I jump compressor It cools good. Today I drove car for awhile before air kicked in. worked good. So where do I go from here. Also wasnt pleased with vac pump. Going to do it again but waiting to see about repairs before I evac.

[Cornbinder89]

So, how do you know it has the correct charge? What do you mean by "system wasn't wanting to cycle correctly?" It is sounding more and more like an electrical problem with the climate control system. How are you "jumping the compressor?

[Whitenight51]

Jumping compressor by relay in fuse box. Static pressure is about 75 lbs yesterday temp about 75 so I would think it would start. Now thank you for your interest. So how would you check climate control. I also have to take it have fuel gauge problem scanned. When I was charging it back up I didnt think it cycled like it should. Thanx Rick

[Cornbinder89]

Did you add the refrigerant by weight? Static pressure has little to do with amount of refrigerant. If the clutch it self is having trouble pulling in (good 12 volt signal to the clutch wire, but still doesn't pull in) check the clutch gap and adjust.
It looks like the is a Tx valve system and not a cycling clutch (CCOT) system so the clutch should not cycle often.
If the charge is known to be correct BY WEIGHT, and the system cools well with the clutch relay jumped, then it is the control side of the system and not the refrigeration side.
I am a heavy truck guy and don't mess with car except my own, so don't know all the common areas on yours.
Likely is going to take a scanner and a set of gauges, to see if what the transducer is "telling" the system matches what the gauges say. From there it could be the HVAC head or controls in the cabin or? AS I say not my area.

[Whitenight51]

Thanx for your answer. went out and stated the car to move it, a/c came on like it should. Put gauges on to see what I had.
175 over 32 or 34. About like my blood pressure. Are temp 82? air coming out of vent 55. It would work every time first time I wouldn't be bothering you. I live in W.V. Fans did not need to kick on, pressure would go up to 200 over 40? then come back down. Owned one heavy truck that was enough. CYL.

[Cusser]

Did you add the refrigerant by weight? Static pressure has little to do with amount of refrigerant.

Good advice.

Did you add the refrigerant by weight? Static pressure has little to do with amount of refrigerant. If the clutch it self is having trouble pulling in (good 12 volt signal to the clutch wire, but still doesn't pull in) check the clutch gap and adjust.

I fixed a slipping/intermittent AC clutch on my 1998 Frontier a few years ago by removing an AC clutch spacer/shim. I didn't even need to remove the AC belt to do that.

[Cornbinder89]

Pressures are close to the ball-park, a bit high, condensing temp 38 deg above ambient, and the low side is a little high as well. 35-39 deg boiling temp (with R134a).

[Tom Greenleaf]

? If this uses shims for clutch air gap need to know if it's wrong now? IDK .020" or like a folded business card common type of paper is close,