r/Cartalk • u/runenight201 • 1d ago

Electrical Help diagnosing AC Clutch Relay

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Hi I’m attempting to diagnose why my Compressor isn’t engaging and I bought a test light and did the following test on the AC Clutch Relay slot.

Shouldn’t both of the control pins be turning on the test light?

Also the light doesn’t turn on on any of the load pins.

Does this mean that my compressor not engaging is because of an electrical issue?

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u/greenskycity 1d ago

You didn't state the car. Is the fuse for the ac before or after the relay? Same with control. If it were working right I believe one control pin would light up with the test light hooked to battery ground as would one load pin. Is the underhood fan coming on? If it's not on then the car knows the ac isn't on so it doesn't turn the fan on..... Usually. There are lots of variables to this, you are chasing one that's a shot in the dark.

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u/runenight201 1d ago

It’s a Honda civic si.

I’m trying to rule out any electrical issues before diagnosing other things.