When I Press Ac Button Car Gets Ice Cold - Then Car Turns Off!

[startacus]

That's right - its almost unbelievable!

Car is a 1995 SC400. 179K miles.

I purchased this car used from an owner whom kinda neglected the car mechanically. One of the highlights though WAS the cold AC. The AC works and blows very cold. No problems with fan, fan speed, temperature selection, etc.

However, when the car warms up, so it seems, 2 minutes tops, the car will turn completely off when the AC button is on. When you attempt to restart, the car will not start until the AC button is turned off. If the car does start, there is almost no acceleration at all. But when you turn the button off the car runs fantastic. Just no cold air. And if you're driving and press that button the entire car will die!

I noticed this problem with the AC get incrementally worse until I noticed the alternator was getting weak as well. I ended up replacing the alternator last week. I was truly hoping the AC problem would disappear with the newfound amperage of the new alternator however the problem returned.

I dont know if this will help, but I noticed that someone has hacked into the original alternator harness (there is no connector at all at this time). They used wires that appear to me to be very thin (maybe 18 or 20 guage), and they connected these wires to the alternator using female spade connectors.

I've also noticed (dont know if this is related or not) but when the car is at a stop light when the AC is actually working, the RPM's drop to 500 or so (real low), and sometimes I actually have to put my foot on the accelerator to keep it from stalling out.

I did have the alternator tested prior to having it installed, and everything else in the car seems to be working fine with the exception of this AC issue.

Can anyone shed some light as to what I could/should do? Any help would be appreciated. Thanks alot!

[startacus]

Anyone have an idea? Thanks

[rekit]

Is the compressor dragging or is it an electrical issue? Take the belt off the ac compressor (if that's all the belt turns, or just unplug the compressor clutch wire), and turn on all the ac switches. Does it NOT slow down? Maybe it's got too much freon or bad bearings. There is also a switch-I forget what it's called,(dashpot?) but most cars have them. It speeds up the motor by pushing the throttle open a little when the ac comes on. It should speed up enough to make up for the drag of the AC-no more, no less. Mine (93 sc400) works too well and speeds up too much. I think it's adjustible, I just haven't looked for it yet. Your low voltage could have been from just idling too slow.......

[rekit]

Is the compressor dragging or is it an electrical issue? Take the belt off the ac compressor (if that's all the belt turns, or just unplug the compressor clutch wire), and turn on all the ac switches. Does it NOT slow down? Maybe it's got too much freon or bad bearings. There is also a switch-I forget what it's called,(dashpot?) but most cars have them. It speeds up the motor by pushing the throttle open a little when the ac comes on. It should speed up enough to make up for the drag of the AC-no more, no less. Mine (93 sc400) works too well and speeds up too much. I think it's adjustible, I just haven't looked for it yet. Your low voltage could have been from just idling too slow.......

Is it actually killing the engine?

[startacus]

Thanks for your answers REKIT. I will definitely try that tomorrow or Tuesday.

It DOES kill the engine when that AC switch is manually hit. I could be in traffic or at a stop light. I could even be driving 70mph down the road. When that switch is depressed I have a 90% chance the engine will die. Further, acceleration is extremely difficult if the car does not turn off and if I let off the accelerator it does indeed die!

This AC issue was not an issue (that I knew of) when I purchased the car. However, a few weeks into having the car I noticed that things were slowing down - windows, etc. Just thought it was me. Then one day the car died and I could not get it cranked until I turned the AC switch off. That day I thought it was a fluke because the AC switch was off but I was still getting cold air. I have since learned that the condenser was probably still cold which is why I had cold air after the fact. When the lights got dim I knew I could also have an alternator or a battery issue. Then the car died. I had the battery charged and put it back into the car which lasted about 3 days before it died again. Had it charged again, took it to Auto Zone whom told me I was only getting 10 volts on charge. Advised me to replace it. Had alternator replaced with what I thought was a 100-amp alternator and had it retested. They said alternator was putting out 84-amps at 13.9 volts. However they advised me I may also have a battery issue.

The alternator is definitely working and everything in the car runs fine outside of the fact that of this AC issue. My thoughts were this is some sort of current issue or wiring issue with the compressor not getting enough power to run or the compressor is taking away too much power from everything else. I hadn't thought of it being the compressor itself because when it turns on the air is ICE COLD!!! But when its off of course there's nothing cool about it.

[startacus]

Belt is serpentine and it runs everything. Alternator. Power Steering. Compressor. Etc.

[rekit]

When you say it killed the engine I thought is was too much drag, but if you're going 70 and it dies it must be electrical-unless it locks up the back tires<G>. It may be time for pro help on this one-sorry. Let us know what you find. That wiring job is your first clue.