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'93 A/C Q's

T

trap4x4

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Medicine Hat Alberta
Hi guys...

Trying to trouble shoot my ac. Not 100% sure the compressor is kicking in. Should there be power to this plug when ac is on? I have no power to it. tried to trace the harness but kinda lost ambition when it clustered up in back of block...

I have power to the rear plug on the compressor btw.


 
Yes, whe nth A/C is on there should be power to that plug as that is teh compressor clutch plug. The other one is teh high pressure switch and it should have power, as well as the one on teh silver canister mounted up by teh firewall. Teh one mounted to that canister is the low pressure cycling switch, and it is the one that controls power to the clutch and turns it off and on at the correct temp(via pressure), and is a common failure point on these trucks.
 
The switch on the silver canister also kicks out when the system is out of gas. It should have zero ohms across it. If it reads open the system is empty of gas/freon or it is bad.

The rear compressor high cut out switch should be "closed" and in 0 ohm across the contacts as well. Should as some years may have used this switch for different things like going into rec mode on high system pressure or not even had a switch there at all. However with 134A it should be used as a high pressure safety cut out.
 
WarWagon said:
The switch on the silver canister also kicks out when the system is out of gas. It should have zero ohms across it. If it reads open the system is empty of gas/freon or it is bad.

The rear compressor high cut out switch should be "closed" and in 0 ohm across the contacts as well. Should as some years may have used this switch for different things like going into rec mode on high system pressure or not even had a switch there at all. However with 134A it should be used as a high pressure safety cut out.
Click to expand...

The switch in the compressor was always a high pressure cutout switch that would open around 375 or so. The recirc switch is normally mounted up on teh condenser outlet line and will close around 310-325.
 
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