AC clutch not responding

hello Bronco friends! hehe
i have one problem that i ve'benn read in here. but i didn't find the answer.

first..
it's a 1988 full size bronco. 5.8
when i turn on the truck, and turn on the AC the clutch dont engage..
i already jump with the batery the clutch.. and i have a success.. it engage..
i checked the voltage in the conector in the clutch .. and it's 11.50V.. when the truck it's off and the AC on.. and when the truck is ON. the voltage in the connector is 12.50V.
so.... the voltage it's ok!! and all the functions are alright..
but... if the voltage it's ok..
why the clutch didn't engage when i connect the original cable for the compressor.????

other test.. the truck OFF...but the AC ON... we have 11.50V and... didn't engage...
test 2... the truck OFF.. the battery 12V and jump the clutch.. and engage!!!

why does not engage with the original cable?.. it only have .50V of difference..???

Half a volt shouldn't make any difference. I'd clean all the electrical connections in the AC system, especially the wiring to the clutch on the compressor. Clearly the clutch is OK. One thing I noticed about your thread was that with the truck off and the AC on you had voltage. Shouldn't be that way because the low-pressure switch on the accumulator-drier should be off due to no pressure when the engine is off. Take a wire of paper clip and jump the electrical connection at the low pressure switch. If the AC clutch does come on the low-pressure switch is at fault.

Half a volt shouldn't make any difference. I'd clean all the electrical connections in the AC system, especially the wiring to the clutch on the compressor. Clearly the clutch is OK. One thing I noticed about your thread was that with the truck off and the AC on you had voltage. Shouldn't be that way because the low-pressure switch on the accumulator-drier should be off due to no pressure when the engine is off. Take a wire of paper clip and jump the electrical connection at the low pressure switch. If the AC clutch does come on the low-pressure switch is at fault.


oh ok!!!
thanks... i'll do it!!!

i checked the switch and all it's ok..
the problem here was the refrigerant valve.. it leaks a little. and one hose has little oil. so... i open the valve like 10 seconds or more. and turn On the truck.. and the AC clutch engage!!... so i learned one lesson.. it' needs refrigerant and a new valve and one hose.

thank you! :)

Eww, glad to see you figured it out.