I'm still having problems with my A/C causing my engine to stall and then die. It seems my earlier post has fallen down too far on the list to get any attention, so any help would be appreciated. I've checked the A/C clutch, the IAC, the TPS, the battery and the alternator. Everything seems to be fine. When I turn on the A/C to normal or max, the battery guage drops way down then goes to mid range (where it normally is), then soon after the engine stalls and dies when I come to a stop. I turn the A/C off and it cranks right back up. This only happens when I turn on the A/C. It doesn't happen when I turn on the heat, so I don't think it's a switch issue, but what the hell do I know. Any ideas?

 

does the truck feel like it has alot less power then its suppose to when you have the a/c on?

 

No, it seems the same to me. I did a little more testing yesterday, and the battery guage does drop when I turn the heat on also, it just doesn't cause the engine to stall and die. I watched it really close and it does have a subtle flicker when I hit the switch, but not like when I hit the A/C.

 

the a/c puts strain on the motor and the heat doesnt. the only thing causing the gauge to go down is the blower motor. have you checked your fuel filter. or put a fuel pressure tester on it. if you take off the belt see if you are able to turn the compressor. not just the pully but as if the clutch was engaged (meaning the center part also). you should be able to do it with your bare hands. it shouldnt be super tuff to turn.

 

No, I just turned the pulley. I'll do the other test and see if it turns. I'm starting to think this is a voltage issue. I did a lot of other tests yesterday, with other electrical things like lights and the radio and I can barely see the battery guage drop if I watch it really close. So, today I'm breaking out the meter and checking all of the grounds, battery, alternator and the fuse block.

 

Just to clarify, in your last a/c thread, I suggested running the KOEO self test with the a/c turned on, and check for codes. Did you try this and what were the results?

 

Just a thought. I had an 89 mustang that began to do some strange electrical things, dying etc. Voltage fluctuated and the fuel pump sounded strange when it primed. I had the charging system tested at a local parts store and it checked out fine, actually putting out a little high. I changed the fuel pump thinking something was going on with it because it sounded so odd. A couple of days later it started doing it again. Had it checked again and the voltage was all over the place. I replaced the voltage regulator on the alternator, about $40 and that fixed it.

 

Forgot to post results: Ran KOEO test with A/C on and all other loads off and got an "all clear". I found a loose ground and tightened it and it now A/C doesn't cause stall out but still causes guage to drop when blower is on high. Batter y guage drops a little bit with each fan speed increase but won't cause the truck to stall and die anymore. I also suspected the voltage regulator, but I can't find it. I've been told it may be inside the alternator. My A/C compressor also sounds like crap when it kicks in. I don't know any way to describe it other than it sounds like it's gonna check out on me and will likely be expensive when it goes!