climate control panel

1993 CHEVROLET SILVERADO
197,000 MILES • 5.7L • V8 • 2WD • AUTOMATIC
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OPPER79
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Hi, the AC/heater control went out. no display or power. I checked the 25 amp fuse and that was fine. I then tried two different used modules (from junk yard) and still did not work. I know they both could be bad but one should be good. How do I identify power and ground contacts for cleaning? Anything else that could make entire control go bad? Can PWB in control module be repaired? Thanks
Jul 23, 2017 at 7:40 PM
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WRENCHTECH
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It is powered by a fusible link, probably at the starter or a power distribution block on the firewall.
Jul 23, 2017 at 7:52 PM
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WRENCHTECH
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Here is the wiring diagram.
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Jul 23, 2017 at 7:55 PM
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OPPER79
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If I can trace it back, will I be able to check the link with an ohmmeter?
Jul 23, 2017 at 8:15 PM
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WRENCHTECH
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Pull on it. If it stretches, it is burnt out. Use only fuse wire to replace it, not regular wire.
Jul 23, 2017 at 8:17 PM
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OPPER79
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If you could take a picture of a fusible link, I would appreciate it. Otherwise, thanks for the advise.
Jul 23, 2017 at 8:20 PM
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WRENCHTECH
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It is just a small section of wire that is specially designed to melt when overloaded.
Jul 23, 2017 at 8:22 PM
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OPPER79
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thank you, Sir.
Jul 23, 2017 at 8:44 PM
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STEVE W.
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Usually you will find the ends of them where they are bonded into the main harness covered with thick silicone seals. The one you want will be rust colored and comes out of the battery junction box.
Jul 24, 2017 at 2:31 AM
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OPPER79
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The battery junction box is on the firewall in the engine compartment? Can I check with ohmmeter?
Jul 24, 2017 at 10:39 AM
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WRENCHTECH
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No, use a test light or voltmeter. You are looking for voltage beyond the link.
Jul 24, 2017 at 10:49 AM
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OPPER79
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Thanks.
Jul 24, 2017 at 11:19 AM
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STRAILER
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Please use 2CarPros anytime, we are here to help. Tell a friend please.

Cheers, Ken
Jul 25, 2017 at 12:41 PM
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OPPER79
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I checked the voltages at the connector at pin 12 and A(Battery and Ignition) and had 12V on both. I assumed the 2 used control units were good but I'm thinking maybe they are bad.

Attention Kmart shoppers, I still need help.I have tried 5 used modules. we have verified ignition and battery power and that we have a good ground to connector.....but still no display or operation.
Jul 27, 2017 at 5:33 PM
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STRAILER
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You must have a wiring issue, here is a guide and a wiring diagram so you can do some testing.

https://www.2carpros.com/articles/how-to-check-wiring

Please let us know what you find.

Cheers, Ken
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Jul 31, 2017 at 11:16 AM
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OPPER79
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I thought the ground at the connector was good, but it wasn't. I tapped into the ground wire and ran another so I have the display lit up on module. I try different buttons on control unit and I can hear the relays clicking but I have no fan or air. Any ideas?
Sep 5, 2017 at 10:28 AM
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STRAILER
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Even though the the relay clicks it still can be bad, here is a guide that will help you test them.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Please let us know what happens.

Cheers, Ken
Sep 5, 2017 at 11:57 AM