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Jerry, Master Mechanic
Category: Chrysler
Satisfied Customers: 16825
Experience:  ASE Master tech. 30+ years mechanic, shop forman, service manager
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2003 pt cruiser.with the a/c on the cooling fan does not come..wiring

Resolved Question:

have a 2003 pt cruiser.with the a/c on the cooling fan does not come on.looking at the wiring should be on when a/c is turned work's when motor get's hot.i'm thinking computer is not grouding it
Submitted: 7 years ago.
Category: Chrysler
Expert:  Jerry replied 7 years ago.

Hello and welcome to Just, Super mechanic here. About your vehicle.


The engine will still have to reach a certain temperature for the radiator fan to come on with the A/C on. Here is a rad fan operation chart. There might not be any problem with it.







Radiator fan operation is control by the Powertrain Control Module (PCM) with inputs from the temperature of the coolant, which is sensed by the coolant temperature sensor, and vehicle speed which is measured by the vehicle speed sensor. The PCM turns on the fan through either the high or low speed fan relay. The PCM provides a ground to the relay's control circuit. The fan relays are located in the Power Distribution Center (PDC) (2). Refer to the label beneath the PDC cover for location of fan relays.

Refer to Radiator Fan Operation Chart for fan operation specifications. For fan circuit wiring diagrams, refer to WIRING DIAGRAMS.

If the cooling fan is inoperative or a Diagnostic Trouble Code (DTC) related to fan control has been set, refer to the appropriate Powertrain Diagnostic Information for diagnostic procedures.


Customer: replied 7 years ago.
i under stand what your saying.with the a/c gauges hooked up,the high side pressure is going over 450psi and still no fan
Expert:  Jerry replied 7 years ago.

You will want to check the pressure on a scan tool to see if the PCM is getting the correct A/C pressure, to command the fan on.









Customer: replied 7 years ago.
i think the computer ground is modis scanner would not talk to the computer in the freind work's at a local dodge store,and he could make the high speed fan work but not the low speed,use ing the drb 3
Expert:  Jerry replied 7 years ago.
That could be but you will want to be sure that the low speed relay is good and it is getting the ground from the PCM
Customer: replied 7 years ago.
the relay is good
Expert:  Jerry replied 7 years ago.

So let's see.


The A/c pressure is getting up around 450 PSI, and the PCM knows it.


The PCM is able to command the cooling fan on high, but it doesn't.


The relay is good, (high and low)


Sounds like the PCM

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