1992 taurus a/c

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----

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.

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

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

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