C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

1989 AC Compressor Clutch Diode

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Old Sep 24, 2017 | 12:11 AM
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Default 1989 AC Compressor Clutch Diode

Got a question... My 1989 C4 AC is not working because the Air Conditioning Compressor Clutch Diode got broken. Here's the problem... that part is aparently unobtanium. Nobody makes it. Eckler's has the part for 1990-1996 C4, but it isn't exactly the same, although it sure looks like if I cut both sides and put in the newer part it should work. Does anyone out there who knows these AC systems know if that is correct? FWIW, the Eckler's PN for the newer part is 25-129469-1
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Old Sep 24, 2017 | 12:36 AM
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Originally Posted by ihatebarkingdogs
I thought the clutch diode is across the two terminals on the coil, band towards (+) side? If it is, the diode has nothing to do with the clutch working or not. It can be broken in two, and the clutch should still work. The diode is for spike suppression when the coil field collapses when the coil turns off.


You can use any diode you want for the suppression. Band towards the Positive side.
The whole connector is smashed and it will work intermittently if I jiggle it just right, but it won't stay working when the car is driven even if I tape it together. I need to replace the whole thing. If Eckler's still had the part for the older models I'd be set. I just don't know if I can substitute the new connector setup even though I know it won't plug directly to other parts.
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Old Sep 24, 2017 | 03:20 AM
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Originally Posted by softwarejanitor
Got a question... My 1989 C4 AC is not working because the Air Conditioning Compressor Clutch Diode got broken. Here's the problem... that part is aparently unobtanium. Nobody makes it. Eckler's has the part for 1990-1996 C4, but it isn't exactly the same, although it sure looks like if I cut both sides and put in the newer part it should work. Does anyone out there who knows these AC systems know if that is correct? FWIW, the Eckler's PN for the newer part is 25-129469-1
Hi you can use a regular diode, the ecm uses the 12 volt signal to adjust idle speed. You may have a bad wiring connector as well.
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Old Sep 24, 2017 | 04:25 PM
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Originally Posted by gerardvg
Hi you can use a regular diode, the ecm uses the 12 volt signal to adjust idle speed. You may have a bad wiring connector as well.
I need a whole new connector, as I said above the connector is completely smashed. That's the actual problem. I think my diode itself may be fine but the plastic casing is crushed and not usable. I just want to know if the diode and connector that Eckler's sells for 1990-1996 can be retrofitted onto a 1989.
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Old Sep 24, 2017 | 04:28 PM
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Originally Posted by ihatebarkingdogs
Ahhh. Now I understand.


I looked at an image of the 10PA20 clutch coil. There are two wires. So there are also two wires into the car's harness. Can't you just splice them together, eliminating the OEM connector? And when you do, use any 1 or 2 amp diode. Put the band on the diode towards the Positive side. (In most GM systems, this is a Dk Green wire, but I didn't confirm this from an FSM or observation). Or get any generic 2-pin connector, and splice BOTH sides.
I could I suppose, but I'd rather get a connector that at least looks right and is designed for the purpose. The Eckler's part for 1990-1996 I referenced includes the pigtails to splice on both sides, I just want to know if anyone has used one on a 1989 before I order it. Yeah, something else may be cheaper, but the Eckler's part is about as close to "correct" as I can apparently get anymore.
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