A/C clutch connector / diode?

[gktbay]

97 XLT … I am needing to replace the diode within the power wire to the a/c compressor clutch, any recommendations? The picture shows the factory grouping of additional wire and diodes found within a wire covering.

 

[J_C]

It looks like just a standard diode in parallel with the clutch coil to prevent back EMF from it when it shuts off. Is it built into some connector or just soldered/crimped on the harness or ??? I'd just get a regular, high (few hundred) voltage rated, 3A+ diode if it just gets put in series on the wire instead of coming built into a Ford part # connector/pigtail.

What do you mean by "the picture shows..."? What picture? I don't see one on your post. The diode just reverse-polarity shunts the power input wire to ground when the coil back EMF happens on power down, just have to make sure the diode is put in with the correct polarity, with its anode facing ground and cathode (often marked with a stripe) facing positive clutch power wire.

 

[gktbay]

 

[gktbay]

 

[gktbay]

Thanks for your reply. In my past, our 98 XLT had the similar problem which I back then resolved with a salvage yard visit contribution.

This 97 is my son’s - after the successful renewal of his a/c system’s major components and flush - working well then out of nowhere, the clutch will engage and within seconds disengage… remaining so.

 

[J_C]

I'm not sure what I'm looking at in the pics. I see the wire of course but not the diode itself. Is it in the sheath with the yellow triangles?

I wouldn't expect a bad diode to disengage the clutch, but you can check it with a multimeter.

How to Test Diodes with a Digital Multimeter | Fluke

Learn how to test diodes with a digital multimeter.

www.fluke.com

 

[gktbay]

I'm not sure what I'm looking at in the pics. I see the wire of course but not the diode itself. Is it in the sheath with the yellow triangles?

I wouldn't expect a bad diode to disengage the clutch, but you can check it with a multimeter.

How to Test Diodes with a Digital Multimeter | Fluke

Learn how to test diodes with a digital multimeter.

www.fluke.com

Yes, presumably so. Historically with our ‘98, I was crap-shooting with an acquired replacement from my local salvage yard and it resolved the issue back then.

No luck yet in the local yard, this post is my effort to find a replacement resource and/or be coached on how to construct a much needed replacement to chill things down for the ‘97.

 

[J_C]

I'd first make sure the wires are in good condition with minimal resistance end to end. If the diode is blown you can get a diode anywhere to splice in. Most basic non-automotive type I'd pick would be something like a 1N5404 (or 1N5406, 1N5408, etc), about 50 cents each but I'd avoid chinese generics. Might be cheaper on amazon or ebay once you factor in shipping.

https://www.digikey.com/en/products/detail/onsemi/1N5404G/1485529

I should have mentioned that the diode needs disconnected to measure it, can't be done while it is still plugged in, in parallel with the clutch coil or else it will read like it is failed closed from conducting in both directions when it's just the clutch coil resistance causing that.