A/C Compressor Zener Diode to stop radio popping

Bernie Benz b.benz at charter.net
Thu May 7 11:21:08 PDT 2009

Zener not needed, any diode of 50V and 1A will do fine. Such a diode  
is in the clutch relay and is open if your symptom is transient  
voltage spikes which results in radio noise and other more serious  
problems. If this diode shorts the compressor will not cycle under  
thermostat control, runs all the time, BTDT. Open this relay and  
replace the diode. It‘s the one across the relay contacts.


On May 7, 2009, at 8:26 AM, Kenneth Keith wrote:

> Hey Listers,
> Does anyone know where I can find the appropriate Zener Diode to use
> with the a/c compressor (patient is a 200q20v) to stop the feedback
> popping when the clutch cycles?  I found some on Mouser.com but they
> are sold by large quantities and I just need one.
> http://www.sjmautotechnik.com says it needs to be one with an 18v
> breakdown voltage.
> Has anyone done the mod?  It's described here:
> http://www.sjmautotechnik.com/trouble_shooting/elec.html#click
> Cheers,
> Kenneth
> _______________________________________________
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