1990 4AFE A/C problem - Toyota Nation Forum : Toyota Car and Truck Forums

nickmorin99 · 05-18-2004, 07:52 AM

The A/C in my car stopped working. I know the system is charged so its not low pressure. I know the compressor works as well. I hooked it directly to the battery and it blows 50 degree air out. The problem is that the it dosent turn on with the controls on the dash. I have checked the 10 amp flat fuse in the passengers side kick panel and it turned out good. Also the AC MC (I think it said MC on it) relay under the hood is woking. Are there any other fuses for the A/C circut? Idle on the car also goes up when the inside A/C button is pressed.

newbi · 05-18-2004, 10:44 AM

How do you know its charged? My best advice to to hook up a set of gauges to it, to monitor the pressures. I bet you'll find it low on refrigerant( leak somewhere, it doesn't just evaporate) or that the pressure switches have gone south.

nickmorin99 · 05-18-2004, 02:09 PM

When I swapped it over from R12 to 134a the guage said it was full. It took 2 cans of 134A and the system was full of R12 before I swapped.

newbi · 05-18-2004, 03:58 PM

Believe me, things can (and do) change with automotive A/C rather quickly.. If you did the conversion correctly, you would have disconnected all the lines, blew the evap,condensor and metering device with cleaner to remove ALL the oil, installed new "O"rings and filter/drier, readded the correct amount of PAG oil, pressure checked entire system, then pulled an hour vacumn before recharging with 134a. If so, any one of the connections could have a leak.
If you just did a" dump and gas" swap, your A/C won't last long. The different oils used for R12 and 134a are not compatable. Also, you probably contaminated the system with air or debris which break down into acid (which eats up the entire insides of your system).