i have 30 low and 200 high side on a 60 degree F day. the a/c cycles constantly. comes out cold while its on for a few seconds. i shorted the low/high side switch and it still cycles too much.shouldnt that make it run all the time? what else is telling it to cycle? i do have a ck eng light for the knock sensor i havnt bothered to change yet.

The pressure switch is on top of the accumulator over on the side of the passenger strut tower. Is that the one you jumped? What method did you use?

 

There is also a thermal switch on the evaporator, and a thermal switch in the compressor clutch.

yes that is the one. i used an paper clip.even if it was low or high shouldnt it run for a minute instead of 4 seconds before it cycles off.? 

yes that is the one. i used an paper clip.even if it was low or high shouldnt it run for a minute instead of 4 seconds before it cycles off.? 

If compressor cycles at 4 seconds..........then either low, or over filled on freon.

Edited April 25, 201411 yr by Rooster2

I would try addi g a bit of Freon to it get the pressure up another 50psi. I had a mazda running the same pressures the other day and cycling constantly zo I bumped up the charge a bit and it ran great and got nice and cool

i got about a 1/4? can more in it. took 20 minutes with it cycling like that. up about 50 pounds. its better but not normal. why wont it run all the time with the high/low switch jumped? if i unplug the switch it wont run. jump the harness plug and it runs and cycles.

 

i leave it like this for a few days and see how it is on the highway and if the pressure stays the same by monday. ive done many a/c jobs and this one just doesnt feel right.im missing something unless a thermol switch is acting up or this system is very sensitive to the ammount of charge.

Edited April 25, 201411 yr by auto2

Control of the AC relay goes through the thermal switch on the evaporator core. If the switch is malfunctioning or senses the core is too cold it will cause the compressor clutch to cycle.

 

If you have a thermal switch on the compressor there will be a 3 wire plug on/near the compressor. This is in-line with the pressure switch and can be jumped in the same manner.

Control of the AC relay goes through the thermal switch on the evaporator core. If the switch is malfunctioning or senses the core is too cold it will cause the compressor clutch to cycle.

 

If you have a thermal switch on the compressor there will be a 3 wire plug on/near the compressor. This is in-line with the pressure switch and can be jumped in the same manner.

ok thanks! so ill jump the pressure switch and the thermal switch on compressor and see what happens. the switch on evap is hard or easy to get to?

Evap switch is not easy to get to. Can't jump the evap thermal switch.

we will eliminate all other possibility's and then assume the evap switch is bad. i had a car once that i got a universal capillary tube adj switch. taped it to the low pressure line and made my own harness to the clutch.just this car needs the fans turned on at same time. hummmm,