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Dr.Automotive, Auto Mechanic
Category: Chevy
Satisfied Customers: 3803
Experience:  Automotive Degree Dealer Experienced
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Chevrolet Silverado 2500 HD LS A/c not working compresser

Customer Question

A/c not working compresser won't even kick on. Fuse under dash and hood both fine. Tried tapping clutch but no luck. Ran fine last summer
Submitted: 5 years ago.
Category: Chevy
Expert:  Dr.Automotive replied 5 years ago.

snapontech :

Welcome to Justanswer

snapontech :

1. Bypass the A/C high and low pressure switches and check for compressor operation.

2. Check the A/C compressor relay command.

3. If the A/C relay command is "ON" but the compressor stops check for Battery Voltage (B+) on the Dark Green wire at the A/C compressor.

4. If there is no voltage at the compressor, switch the A/C relay with one of the same number in the fuse block.

5. If there is voltage at the compressor, check for a good ground on the Black wire at the A/C compressor.

6. If the powers and grounds are both good but the compressor is not engaging, check the compressor clutch for being open.
snapontech :

Possible causes

Air Conditioner (A/C) Compressor Relay
Compressor Clutch
High Pressure Switch
Low Pressure Switch
Powertrain Control Module (PCM)
snapontech :

Most of the tests need a scan tool to do this but You can replace the ac compressor relay and if that doesnt work most likely the clutch has failed

snapontech :

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