Automotive Air Conditioning Information Forum (Archives)

nedzad1 on Thu May 15, 2014 1:56 PM

Year: 94
Make: Chrysler
Model: Concorde
Refrigerant Type: 134A
Pressure Low: 35
Pressure High: 250
Country of Origin: United States

Working on 94 Chrysler Concorde. When AC is on compressor comes on , getting high high side pressure, close to 250. Found both radiator fans not coming on. Switched the relays with same relays used for something else, no fans coming on. Removed connector from one motor and it has 3 pins. It does not seem to be getting power. It is dual fan and it appears to have some module between them. Before I order new fan assembly, let me know if there is something I can check before removing the fans.
Thanks

nedzad1 on Thu May 15, 2014 5:24 PM

Removed fans relays and somehow dabs turned on now AC clutch will not turn on

nedzad1 on Thu May 15, 2014 5:30 PM

Anybody has expirience with Chrysler concorde? The latest I found is that when I remove the rdiator fan relay, low or high one fan will work. Other fan never works. If I bypass the ac clutch relay the compressor wil lalso run. I am thinking that I have 1 bad fan and also bad pressure transducer. The pressure transducer is 3 wire switch, not sure how to test it. While removing the fan relay and shorting pin 1 and 3 on clutch relay to enable compressor the cold air blows.


Edited: Tue May 20, 2014 at 9:50 AM by nedzad1

mk378 on Tue May 20, 2014 10:06 AM

Most systems with controlled fans are designed to turn them on around 275 psi. It should go up much higher than 250 with the compressor running but the fans are off. Are you sure the system is properly charged?

Edited: Tue May 20, 2014 at 10:12 AM by mk378

nedzad1 on Wed May 21, 2014 2:23 PM

So you are saying on this system the fans don't have to be on unless the high side is above 250 PSI. Every car I worked on the fans comes on right away. This is something new we learn every day. Can you confirm again please.
Thanks

mk378 on Wed May 21, 2014 4:25 PM

I'm saying that it seems too early to conclude that there is a problem with the fans. It appears to not be the main problem with the car. With an otherwise normal A/C system except for no condenser airflow, with the car sitting still and the A/C on in hot weather (What is your ambient BTW?), the high side would quickly go up over 400.

Edited: Wed May 21, 2014 at 4:26 PM by mk378

nedzad1 on Thu May 29, 2014 11:50 AM

It's not low on Freon, its running 35PSi and 250 when compressor clutch jumped. Also I changed the pressure transducer same problem exist. The clutch will not come on unless relay is jumped and relay is also new. Any other idea?

Jag987 on Thu May 29, 2014 1:16 PM

Pressure is a lousy way to determine correct charge.

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I bought a can of 134a at w**-mart that had a stop leak, oil, and dye in it. It also had a hose and a gauge, so now I'm an AC pro!

nedzad1 on Thu May 29, 2014 1:25 PM

So what's correct way to determine charge?

HECAT on Thu May 29, 2014 1:45 PM

Refrigerant charge is measured by weight. System performance is measured by pressures. When pressures appear good but performance is lacking; refrigerant charge (by weight) should be verified and eliminated as the cause. If not, you can end up doing a lot of that "chasing your tail" stuff.

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nedzad1 on Thu May 29, 2014 2:08 PM

Ok but isn't this pressure enough to turn on compressor?

mk378 on Thu May 29, 2014 3:38 PM

You get all the cooling performance from the last few oz of refrigerant. The rest is there to take up space until it finally causes that few oz to enter the evaporator as liquid so it can evaporate and make cold air.

Seeing that there is enough to turn on the compressor is, well, enough to turn on the compressor. There won't be any cooling just pumping a little gas around. Like I said before, if you aren't seeing 400+ with the fans off, something is wrong with the refrigeration system.

nedzad1 on Thu May 29, 2014 3:56 PM

I jumped the ac clutch and removed fan relay so 1 fan was running. In this car when you remove fan relay the fan runs, maybe some safety feature not sure. So the pressures are with fan running. Temp outside was 80F. Inside is blowing cold air, when I run as I just explained. the problem I am having is that the ac clutch or fans will not turn on at all. New pressure transducer is installed and all 3 relays (ac clutch, fan high and low) are new. What else can cause clutch and fans not to come on. When I get compressor to turn on then I will follow up on proper charge by weight or anything else. Right now I am trying to figure out why is it not starting. Thank you all for your help.