Climate control panel

Tiny
OPPER79
  • MEMBER
  • 1993 CHEVROLET SILVERADO
  • 5.7L
  • V8
  • 2WD
  • AUTOMATIC
  • 197,000 MILES
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
Sunday, July 23rd, 2017 AT 7:40 PM

16 Replies

Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
It is powered by a fusible link, probably at the starter or a power distribution block on the firewall.
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Sunday, July 23rd, 2017 AT 7:52 PM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
Here is the wiring diagram.
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Sunday, July 23rd, 2017 AT 7:55 PM
Tiny
OPPER79
  • MEMBER
  • 7 POSTS
If I can trace it back, will I be able to check the link with an ohmmeter?
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Sunday, July 23rd, 2017 AT 8:15 PM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
Pull on it. If it stretches, it is burnt out. Use only fuse wire to replace it, not regular wire.
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Sunday, July 23rd, 2017 AT 8:17 PM
Tiny
OPPER79
  • MEMBER
  • 7 POSTS
If you could take a picture of a fusible link, I would appreciate it. Otherwise, thanks for the advise.
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Sunday, July 23rd, 2017 AT 8:20 PM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
It is just a small section of wire that is specially designed to melt when overloaded.
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Sunday, July 23rd, 2017 AT 8:22 PM
Tiny
OPPER79
  • MEMBER
  • 7 POSTS
Thank you, Sir.
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Sunday, July 23rd, 2017 AT 8:44 PM
Tiny
STEVE W.
  • MECHANIC
  • 15,233 POSTS
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.
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Monday, July 24th, 2017 AT 2:31 AM
Tiny
OPPER79
  • MEMBER
  • 7 POSTS
The battery junction box is on the firewall in the engine compartment? Can I check with ohmmeter?
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Monday, July 24th, 2017 AT 10:39 AM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
No, use a test light or voltmeter. You are looking for voltage beyond the link.
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Monday, July 24th, 2017 AT 10:49 AM
Tiny
OPPER79
  • MEMBER
  • 7 POSTS
Thanks.
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Monday, July 24th, 2017 AT 11:19 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Please use 2CarPros anytime, we are here to help. Tell a friend please.

Cheers, Ken
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Tuesday, July 25th, 2017 AT 12:41 PM
Tiny
OPPER79
  • MEMBER
  • 7 POSTS
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.
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Thursday, July 27th, 2017 AT 5:33 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
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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Monday, July 31st, 2017 AT 11:16 AM
Tiny
OPPER79
  • MEMBER
  • 7 POSTS
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?
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Tuesday, September 5th, 2017 AT 10:28 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
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
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Tuesday, September 5th, 2017 AT 11:57 AM

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