1992 taurus a/c

[millerl513]

I am reading 0.4 volts at the a/c low pressure cycling switch connector coupling---I know I should be getting battery voltage at this connector----as a result my compressor will not engage---what might be causing this????? the switch on the dashboard??------a bad diode in the system??? thanks for any help you might be able to provide----

[sahib]

Have you checked both sides of the plug on the harness for voltage? If neither side has voltage, then your dash switch may have a problem or the fuse may be blown. If you have voltage on one side, then the pressure switch may be faulty or the system pressure may be to low.

[millerl513]

neither side has voltage, or very low like 0.4 volts--this is with the connector off of the switch--all fuses are ok--i am supposed to have 12 volts at this plug irregardless if switch is bad or system pressure is low--i have a factory manual and will try and begin some more troubleshooting at the switch--only problem i am not an electrical expert, but i do struggle thru----thanks for your response

[Froze_Tread]

Depending on the switch it could be on the ground side of the system as well. GM loves to do that but i wouldnt put it past ford. THe reasone i say this is bacause .4 volts usually means u have a compontnet on the other side connected to b+ and that the ground side IS working. to check this just put multimeter red wire to B+ which is battery pos and black lead to the connector. cheers

[speeding turtle]

I have the same car but have intermitten A/C operation the Low P switch is supplied by A/C clutch control relay an integral part of a control module mounted under the fan shroud it has about 30 wires coming out of it What controls this relay If anyone has Info to further help