A/C compressor pressure switch help!?!?

[SNOMAN]

Ok so compressor won't engage. I'm reading that a faulty low pressure switch can cause that. Anyone know which one I need?

I might as well replace the high pressure one on the lines as well. Can someone recommend one for that as well?

My truck is a 97 ext cab with 454.

 

[east302]

Is it low on refrigerant? A quick check is to remove the cycling switch connector on the accumulator (I’m pointing to it in the photo below) and put a jumper wire across the two pins in the wiring connector. That will cause the clutch to engage to verify that the switch works.

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The low pressure switch is also called the clutch cycling switch.

 

[SNOMAN]

Is it low on refrigerant? A quick check is to remove the cycling switch connector on the accumulator (I’m pointing to it in the photo below) and put a jumper wire across the two pins in the wiring connector. That will cause the clutch to engage to verify that the switch works.

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The low pressure switch is also called the clutch cycling switch.

Its not low on refrigerant. I brought it in to the dealer today to get charged. It would only engage when jumped at the relay. I'll try that tomorrow. I ended up finding both ac delco switches for the dryer and hose locations so I ordered them anyways

 

[div4scpro]

Have you checked to make sure your AC/heater control panel is working properly. They are notorious for shorts on the printed circuit board that can cause a host of symptoms. Until I modified the circuit board on my AC control I went through more confusing symptoms with the AC system than you can imagine.
The resistor not working properly can also put additional strain on the control panel.

 

[SNOMAN]

Have you checked to make sure your AC/heater control panel is working properly. They are notorious for shorts on the printed circuit board that can cause a host of symptoms. Until I modified the circuit board on my AC control I went through more confusing symptoms with the AC system than you can imagine.The resistor not working properly can also put additional strain on the control panel.

I would assume it is. Everything lights up and the blend doors move as should. The tech states", found the ground side of the ac compressor relay control circuit to be missing. Installed jumper and found the ecm to be able to control the compressor." So to me is sounds like I need a ground but I dont know which prong # on the relay is ground.

 

[SNOMAN]

Ac compressor engages when i jump 30 on the relay with either 86 or 87. All the wire are there underneath

 

[SNOMAN]

It ended up being the ac circuit board on the dash. The ribbon was cut/cracked so I removed the protective coating and soldered it. A/C is working great with the new design compressor. It gets cold fast!

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[brian c lindsey]

could you expand on your statement "new design compressor "?

 

[SNOMAN]

could you expand on your statement "new design compressor "?

Its the denso/four season compressor. It has more pistons in it which supposedly gives a better/quicker charge and less likely to leak. So far it's been working well.

 

[andy396]

@Snoman Can you educate me on this as well. The HT6 was the OE design and know they offer a Sanden style compressor. Is what you’re referring to a 3rd offering?

Here’s the Sanden style offering that I installed on my truck. Happy with it so far.

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