Air Blows Warm but No Check Engine Light On

2004 Malibu Maxx 3.5L.
It is warm now and the AC is not coming on to cool the car.  There is no Check Engine Light on.  Is there a fuse I can check and if so where? Also, if there is no Check Engine light on is it safe to assume no Codes are present?  How do I go about reading the Codes form this car?  Thank You KC



Does the light on the heater A/C control panel light up when you press the button for air conditioning?


Yes, the "A/C Request On" light does come on when depressed.
I did locate the A/C compressor on the car and it does rotate freely.
I looked at the #34 Relay for the A/C clutch (under the hood fuse compartment). I pulled relay #34 it out and buzzed it out.. it does work... coil and N.O. switch. I inserted a jumper in the where relay #34 plugs in in the under hood fuse box to force the A/C clutch to come and and it did engage.
I left the car running. The larger tubing coming from the evaporator would not turn cold with the A/C clutch engaged.


First off, a problem in the A/C system will not set a check engine light or codes.
First you need to check that the freon charge is full. The compressor will not come on if the charge is low. There are sensors in the system that detect a full charge, then allow the compressor to come on. Jumpering at the relay bypasses the pressure sensor and forces the compressor to come. If there is no or low freon, running this way will burn up the compressor. The PCM looks at pressure sensor, then activates the relay which powers the compressor.

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