A/C On - Loss of Engine Power

**wrodriguez** · 11-06-2007, 05:53 PM

Hello Everyone!

I'm a nubbie to this forum! I currently own a 2002 Chevy Trailblazer.

I'm having some weird issue when I turn on my ac. While I'm in park and turn on the ac, it sucks the power and almost everytime, the truck turns off. Now, while I'm driving and turn on the ac, it's ok, the ac cools and cycles on and off just fine. It's just when I'm in park or when I'm coming up on a light I have to turn off the ac or the truck turns off.

Any help would be appreciative. My husband already put 2 cans of freon and replaced all the fuses and that wasn't the issue. The clutch is fine and the compressor seems to work.

**Cableguy** · 11-07-2007, 04:23 PM

Sounds like it should have a scanner hooked up and go for a drive. I've had a mechanic do that for me before. To see what condition is changing fuel, codes etc.

**John W** · 11-08-2007, 06:47 AM

I think your A/C system may have too much refrigerant in it if two containers were added. Then again that system should have R134a not freon.

**wrodriguez** · 11-08-2007, 09:36 AM

Thank you for your feedback!

Yes, you are correct R134a is what was added. But the problem existed before we put the refridgerant. My husband corrected me also, he didn't put 2 he only added 1 and it didn't take the whole can. He quickly realized there was enough in there.

Any more suggestions are greatly appreciated.

**wrodriguez** · 11-08-2007, 09:38 AM

Thank you for your feedback Cableguy! You are right, we may just have to do that, because this issue is definately leaving us stumped.

**unplugged** · 11-08-2007, 10:02 AM

Are you having any problems starting the vehicle?
The a/c is increasing the power load enough to kill the engine. I'm thinking bad battery, but more likely alternator. Unless there is a short in the ac circuit. Put a voltmeter on the battery and see what the voltages readings are when: (all accessories off)

the engine is off
when the engine is idling
when it is at 2000rpm

Voltage at rest should be 12-12.5vdc
Voltage at idle should be 12+vdc
Voltage at 2000rpm should be 14-14.5vdc

I have a meter that measures dc current draw and would test the current load of the ac unit to see if it is in range. You might use a "shadetree" test by putting a lower amp fuse in the fuse panel to see at what amperage the ac unit blows the fuse. Decrease the fuse rating by 5amps at a time and somewhere between the fuse that blows and the one that didn't is your amp load. Do not put a fuse in greater than the factory fuse.

Your local AutoZone can load test the battery and test the alternator as well. (Free test)

**wrodriguez** · 11-20-2007, 03:32 PM

I finally took my TB to the dealership to get looked at.

Of course the fan clutch was bad and needs replacement.

The a/c problem I'm being told, is due to low RPM's. The technician said that when they turned on the a/c it ran way under 600 RPM's and that's why it was causing the truck to turn off.

Simple fix: Throttle Body Service.

Looking at a hefty price to fix both. But I like my truck a lot so I'm going to give it a try. I really hope this works.

Does this make sense to anyone? I take my truck in tomorrow, I'll let yall know how it goes.