2004 Honda Civic

MAURILIOSANCHES

MEMBER
2004 HONDA CIVIC
4 CYL
FWD
AUTOMATIC
46,700 MILES

A/c clutch not working when a/c switch is on

Tuesday, May 25th, 2010 AT 12:34 PM

7 Replies

KHLOW2008

MECHANIC
41,814 POSTS

Hi mauriliosanches,

You would need to check if there is battery voltage at the AC clutch. If no power is available, then you need to check the compressor clutch relay.

Are the cooling fans turning on when the AC switch is operated?

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Friday, May 28th, 2010 AT 12:37 PM

MAURILIOSANCHES

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4 POSTS

There is no voltage in the A/c Clutch. Also the cooling fan is not working.
I think the Ecu is bad or the multiplex, but I do know how to test them.

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Sunday, May 30th, 2010 AT 8:11 PM

KHLOW2008

MECHANIC
41,814 POSTS

Check for power supply to the ac clutch relay.

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Monday, May 31st, 2010 AT 9:22 AM

MAURILIOSANCHES

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4 POSTS

Already checked. There is power, all the fuses are ok, The computer is not sending the signal to the a/c relay. (All wiring connection are good!)

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Monday, May 31st, 2010 AT 1:44 PM

KHLOW2008

MECHANIC
41,814 POSTS

If the relay is not being grounded to activate the compressor, the mostlikely fault would be the PCM. This is a known problem.

At the PCM, use a test lamp to back probe the E18 terminal ( clutch relay, RED wire ) and if the compressor comes on, the wiring is ok and you have a faulty PCM.