I searched the forums and did not find anything helpful.

When I am driving highway speeds my A/C will stop cooling then start again. Last summer I replaced the condenser fan and that was not the issue. It works when at idle but when driving it begins to stop. Seems that the hotter the outside temps are the worse it gets.
I was told that the pressures could not be checked correctly unless they recharged the system? huh?

Please, any info will be gratefully appreciate.

Thanks

 

Sounds like a low charge to me. The warmer it is, the more freon has to evaporate in order to build pressure in the system. If theres not enough freon to evaporate, then it cant build enough pressure to operate efficiently. You can get a recharge kit for around $20-30 with a re-usable guage that will tell you when you have a sufficient charge. It will also be a good idea to rinse out your condensor coil with a water hose prior to topping it off for best results.

 

Well I found a shop that would check the a/c and they said it's almost perfect and could not find a reason to add freon. He said if anything it was almost high but that was because it had been running for a while before I took it in.

I'm wondering if the condenser fan motor I replaced could be bad or have a small short in it to cause it to cut in and out?

Now I wanted to ask one other question.

There are 3 positions on the control panel for the A/C 2 of which are recirculation.
If the switch is set on one of those can that make the a/c stop cooling for a minute or more?

 

On the highway the condenser fan is not needed. The airflow through the fins is more than sufficient. Sure sounds like low refrigerant. You should find two basic settings - recirculate and fresh. Recirculate will give you colder air than fresh.

Does the compressor cycle on and off often?

 

Possibly weak clutch , not staying engaged, I would wire in a test light to ac comp clutch to make sure if your losing command or what. If command is still there and u lose cooling u need to make sure clutch isnt cycling or disengaging probably tough at hi way speeds, video it? Is ac bottom staying lit when u loose cool? Possible weak relay if u r loosing command .

 

@ mike. No it does not cut on and off.
@ joebaum. No the button stays lit.
Someone suggested a thermo sensor on the evap could be weak.

 

Defrost mode will turn the compressor on and off, recirculation mode "can" turn the compressor on/off only if the inside air temperature is cool enough. The condensor fan will turn on and off while parked. So your air works, but gets cool than warm but the compressor is always on and not cycling? If so, dirty condenser coil full of bugs, too low or too high of charge, and possible moisture (water) in the system. That would be my guesses.

 

Well I really did not like the guys explanation of how my a/c was close to being on the high side so a friend of mine knew someone at a shop with some equipment and they checked it for free.

Crossing my fingers that it's fixed.

RESULTS: 1.63 lbs. required. System had 2.74 lbs.

Truck was purchased used. A/C acted up last summer but I missed diagnosis because the condenser fan motor went bad and I just assumed that was the whole issue.

Conclusion: Never assume it's fixed until you do a complete workup.
I should have had everything checked properly last year.

Like a lot of other men. I had a case of MAN SYNDROME=thinking I knew everything..LMAO
Guess Whut? = Dodge forum = awesome answers

Thanks everyone.

 

Well its back. Is the thermo sensor located on the evaporator core or is it located somewhere close?

Anyone know exactly where the DRAIN HOSE is for the a/c evap core?