Jeep Garage  - Jeep Forum

Jeep Garage - Jeep Forum (
-   Troubleshooting/Problems (
-   -   A/C or Blower resistor problem? (

bassnbucks 07-02-2011 09:45 AM

A/C or Blower resistor problem?
So I checked the charge on my A/C and it was low. After finding the low side A/C port I charged the system up with the proper refridgerant (134-a) and now my blower wont kick on. I had the blower resistor replaced last year and took it back to the shop. Coinscidentally they were not able to get it to "act up" and stated that the connections are all ok. They were unable to pull any codes from the pcm and said that I would need to take it to a dealer to have the computer re-programed to see if this would fix the problem or there may be a problem with the auto central head or module. All of which they were unable to complete. As soon as I got in the Jeep and turned on the A/C.....guess what? The air came on for 2 seconds and shut off just like one would expect with a resistor problem. They said they could bring it back in and look at it again but it wouldn't change any their diagnosis and solution.:cool:

One thing I did notice is that when the A/C is on I will hear a whine that coincides with pressing on the accelerator. It does not change pitch when the engine shifts, only if the accelerator is depressed and stops when it is released. Kinda like a fan that is engaging with accelerator depression. The whine is not coming from any speakers as the radio is turned off.

Any thoughts or suggestions on this problem? Got a 1700 mile trip to the deep south coming up and it sure would be nice having the wife and kids all cool and comfy!:thumbsup:

Frango100 07-02-2011 04:49 PM

Re: A/C or Blower resistor problem?
Did you check with the hood open if you could pinpoint the source of the noise? It could be the airco compressor, but also a slipping serpentine belt. is the belt in good shape and is the belt tensioner not at the end of its travel?
Regarding the "blower motor", i think that you are talking about the cooling fan, right? Is the fan working normally when the engine coolant temperature rises above the 210?
The PCM uses a pressure signal from the A/C pressure transducer to switch the cooling fan and compressor. It can be that the refrigerant isn't filled properly, or even the pressure transducer can be fault. You need a DRBIII scanner to test this transducer.

JeepMe 07-03-2011 01:30 PM

Re: A/C or Blower resistor problem?
Did you overcharge your AC system?

bassnbucks 07-03-2011 01:57 PM

Re: A/C or Blower resistor problem?
Not according to the pressure guage on the re-charger kit. But it is in the realm of possibilities if I had a faulty pressure guage.

bassnbucks 07-03-2011 02:00 PM

Re: A/C or Blower resistor problem?
serpentine belt good, tension good. whine present when cooling fan is on or off. Blower does not blow air whether on heat or A/C which leads me to believe its the resistor. Especially when it will kick on for 1-2 seconds when switched to hi then quit.

Frango100 07-03-2011 02:50 PM

Re: A/C or Blower resistor problem?
Sorry, but i think that i misunderstand you. Are you talking about the cooling fan behind the radiator, or the blower inside the car? When you where talking about pulling codes from the PCM, i understood that you where talking about the cooling fan. But now you are talking about that it doesn't work in heat or A/C when switched to high, so this is the interior blower.
Do you have the manual temperature control system?

bassnbucks 07-04-2011 11:55 AM

Re: A/C or Blower resistor problem?
Correct it is the internal blower motor for the climate control. It is an AZC.

bassnbucks 07-04-2011 02:05 PM

Re: A/C or Blower resistor problem?
I did a self diagnostic test on the ac system and came up with code 52 = AI (Recirc) door travel range too large. Now to find out exactly what this means and how to fix it. My gut tells me it's still a resistor problem.

Frango100 07-04-2011 07:45 PM

Re: A/C or Blower resistor problem?
Strange that they where talking about codes of the PCM, the PCM has nothing to do with the blower motor.
The AZC system uses a blower motor controller and no resistor. Many times the problem is a melted connector on the controller or motor, but you had stated that that was checked already. The blower select knob could also be your problem. You can control the blower motor without using the select knob. To do this, you have to do the following:

While in the display fault code mode of operation,
current system parameters can also be monitored
and/or forced. Rotating the left side set temperature
control clockwise will increase the pointer number
while rotating the control counter clockwise will
decrease the pointer number. Rotating the right set
temperature control will have no impact on pointer
value or the value of the parameter being monitored.
Once the desired pointer number has been selected,
pressing either the AC or Recirc buttons will display
the current value of the selected parameter.
right side set temperature display is only capable
of displaying only values ranging from 0 to
99, the left side set temperature display is used
for values greater than 99. If the value is less
than 99, the left side set temperature display
remains blanked.
While a parameter is being overridden,
the system will continue to function normally
except for the parameter which is being manually
For values < 0, the
Gsegment in the left side set
temperature Most Significant Digit (MSD)(or leftmost
number in the pair) will be used to indicate a
negative number. For values between -01 to -99 the
Least Significant Digit (LSD)(or right-most number
of the pair) in the left side set temperature will
remain blank. System control of parameter being displayed
can be overridden by rotating the right set
temperature control in either direction. Rotating the
right temperature control in the CW direction, the
selected parameter value is overridden and incremented
beginning at the value which was being displayed.
Rotating the right temperature control in the
CCW direction, the selected parameter value is overridden
and decremented beginning at the value
which was being displayed. The rate at which incrementing
and decrement occurs is one unit value per

set temperature detent position.

For the blower motor control you need to dial in pointer number 02.
With the right temp control knob you can then control the blower motor from standstill to max and anything in between. In this way you can rule out if the blower motor controller is ok or not.

Frango100 07-04-2011 07:49 PM

Re: A/C or Blower resistor problem?
The code 52 is normally a problem of the end stop of the door actuator which is broken. You can do a system calibration to see if this will clear the fault first:
1. Turn the ignition on. 2. Set the HVAC to auto. 3. Turn the ignition off. 4. Remove IOD fuse. Wait 90 seconds before reinstalling. 5. Start the vehicle. You will hear sound of the doors moving. 6. Do not touch any of the AZC controls for at least one minute to allow the calibration function to run to completion. This forces the system into a recalibrate the full open and full closed position of the doors. But if there is a problem, you might need a scan tool that can pull codes from the HVAC control module.

bassnbucks 07-05-2011 07:34 PM

Re: A/C or Blower resistor problem?
What and where is the IOD fuse. Thanks for the help btw.

Frango100 07-05-2011 09:21 PM

Re: A/C or Blower resistor problem?
The IOD fuse is in the Power Distribution Center at position 15. IOD means Ignition-Off Draw and is for circuits under power even with the ignition switch in Off position. Permanent memory for PCM, TCM, clock and also the airco system are fed via this circuit. Normally when a new car was shipped from the factory, they removed this fuse to prevent the battery from draining.

All times are GMT -5. The time now is 10:08 AM.

Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Copyright 2012 - JeepGarage.Org
The Jeep Grand Cherokee Owners Community