Need AC electrical experts help troubleshooting...

[toms.abpg]

So my 96 ranger 2.3 compressor will not kick on and it’s baffling me. I’m fair with electricity but not an expert by no means. Here’s what I’ve tested

System is charged, have continuity at low pressure switch when unplugged (the 2 prongs in the switch) I also have 12v to ground (1 lead on negative battery terminal) on both wires going to the switch. Here’s where things get funny, I have 12v going to the high pressure switch, but nothing coming out of the switch ( once again, measure with meter on negative battery terminal ). The high pressure switch has continuity between the 2 prongs on the switch and I also have continuity going from the “downstream” side on the switch to the NC lead on the WOT relay. Even if I jumper the switch I still don’t get voltage to the relay, it’s disappearing seems like.... Any help is appreciated....

 

[RonD]

Here's the wiring diagram for 1996 AC

12volts comes from fuse 18 in cab fuse box, it travels thru the dash selector switch when its in AC, AC MAX or either Defrost setting

Comes out of selector on the Purple wire to the first pressure switch, I would use a jumper wire from there to the Black/yellow wire on the clutch, see if you have enough AMPS, not just volts, to activate the clutch

As far as the volts disappearing, besides continuity between the two contacts test to make sure there is no continuity from either contact to the metal pipe, switch needs to be isolated from ground or the pipe its in

 

[toms.abpg]

Here's the wiring diagram for 1996 AC

12volts comes from fuse 18 in cab fuse box, it travels thru the dash selector switch when its in AC, AC MAX or either Defrost setting

Comes out of selector on the Purple wire to the first pressure switch, I would use a jumper wire from there to the Black/yellow wire on the clutch, see if you have enough AMPS, not just volts, to activate the clutch

As far as the volts disappearing, besides continuity between the two contacts test to make sure there is no continuity from either contact to the metal pipe, switch needs to be isolated from ground or the pipe its in

Thank you so much for the diagram, I’ll update tonite when I get a chance to look again

 

[toms.abpg]

Here's the wiring diagram for 1996 AC

12volts comes from fuse 18 in cab fuse box, it travels thru the dash selector switch when its in AC, AC MAX or either Defrost setting

Comes out of selector on the Purple wire to the first pressure switch, I would use a jumper wire from there to the Black/yellow wire on the clutch, see if you have enough AMPS, not just volts, to activate the clutch

As far as the volts disappearing, besides continuity between the two contacts test to make sure there is no continuity from either contact to the metal pipe, switch needs to be isolated from ground or the pipe its in

Here's the wiring diagram for 1996 AC

12volts comes from fuse 18 in cab fuse box, it travels thru the dash selector switch when its in AC, AC MAX or either Defrost setting

Comes out of selector on the Purple wire to the first pressure switch, I would use a jumper wire from there to the Black/yellow wire on the clutch, see if you have enough AMPS, not just volts, to activate the clutch

As far as the volts disappearing, besides continuity between the two contacts test to make sure there is no continuity from either contact to the metal pipe, switch needs to be isolated from ground or the pipe its in

You nailed it, switch was damaged and grounded out on the high pressure line

 

[RonD]

Good work

Thanks for posting the FIX