AC compressor diode

[49FordTruck]

I have a 49 Ford Truck with a 94 Mark VIII drivetrain. I’ve tallied 19,000 miles on it the last few years and recently got AC.

In doing general research I’ve learned that a clamping diode should be part of the AC clutch system to prevent voltage spikes when the field collapses when the clutch is turned off.

I have the factory wiring diagrams and don’t see a diode anywhere other than for the ABS.

Anybody know if Mark VIII’s have a clutch diode?

 

[joegr]

I don't know if they had one, but adding one is a good idea. Connect the anode(+) to the ground or negative side of the the clutch coil. Connect the cathode(-) to the possible (battery) side of the clutch coil.

 

[49FordTruck]

I don't know if they had one, but adding one is a good idea. Connect the anode(+) to the ground or negative side of the the clutch coil. Connect the cathode(-) to the possible (battery) side of the clutch coil.

Yeah I’ve got one on order. I just find it really surprising that these cars don’t have one. They were really pretty advanced electronically speaking.