Hello everyone,
Im new here, so please forgive me if this topic has be discussed. My 98 dodge dakota has 189,000 miles on it. My AC is working intermittently, some days it will run freezing cold, other times the compressor will not stay on and warm air. I have replaced the compressor, orifice (sp) tube, condenser. The heater core and evaporator are 1 year old.

What could be causing my air to blow cold at sometimes and other time hot?. It does not matter what time of day (temp).

Please help
Andrew

 

Does the heat work fine or does it have problems too?

Make sure you're topped up on coolant and it could be the thermostat getting stuck.

 

Does the compressor run and it not get cold or does it just not run.

How are the pressures? Both sides?

 

if the compresser wont stay on. you should check the electrical connections. make sure they are good and snug. may be even wiggle the wire around to see if the snap it more.

i had a similar problem when i went to fix the a/c in my dak. condencer had a hole in it, when i bought the truck. compressor wouldn't kick on. messed with the whole day with no results.. checking with meter, pressures, connections blah blah blah. went back the next day wiggle the wires by the plug in for the compressor it self. then it came on. haven't had a problem since.

 

The heater works great. When the compressor is on it blows cold air everytime. When the compressor cycles on for 10 seconds the off abvolsly warm air.

Could this be a bad switch (low pressure) in the accumulator?

Took it to a shop and they said it was my evaporator. But it still blow cold so I don't think it is the evaporator.

 

What are your pressures? It's the only way to diagnose an A/C problem.

 

you do need to hook up some guages to check your 134a pressure ( high and low side).

when you replaced all those parts, did you put the system on a vacuum? pump the refrigerant system down to get all of the noncondencables out.

 

another thought too. yes the compressor cycles on and off. when it is off. the refrigerant is not moving. there for, not transfering heat as much. however, the fan is still blowing air accross the heater core. maybe that is the heat you are feeling when the compressor cycles off. i remember reading something about that on the forum a while back.