There are several inexpensive hoses with a built in gauge that you can buy. They normally stock them right next to the cans of R134.

 

Just make sure you get a set with low and high side gauges. If you only get the high pressure gauge you may miss a potential problem that would be seen by an abnormal low side pressure.

I just checked and added freon to mine with my gauges from Harbor Freight. Here are my results:

87 degrees ambient, 70% humidity so the chart calls for 24 PSI low, 220 PSI high. I was low on the high side so I added some and got up to 220 but what I noticed is that the high side pressure varies greatly with the fans. The high side pressure drops when the fans are on high and raises when the fans are on low. The difference is as much as 30-40 PSI. The RPMs are also supposed to be at 1000 which is very hard to hit by modulating the pedal. So I cheated for both and used HP Tuners to set the RPM to 1000 and to run both fans. By doing this I was able to get the pressures spot on. Actually I went a scosh high to 24/230. now here's the rub; My passenger side temp is now a chilly 40-42 degrees but my drivers dide is still 57 degrees. So clearly I have a problem with the actuator although I don't have any HVAC codes. I'm going to play with that next.

Can someone explain what exactly is meant be indexing the actuator by two teeth?

 

OK, I'm a little stumped...My high and low side pressures are good, I'm not getting and HVAC codes, I took the drivers side lower dash off and I can see the vacuum diaphram and the electronic actuator way up inside the dash. If I rotate the temp **** the vacuum disphram goes up and down as it should moving the flap inside the airbox. Is it that the actuator need to be 'indexed'? Can someone point me at the threads regarding pulling fuses and disconnecting the battery? I'd like ot try all of this first because looking at the Helms the entire dash needs to come out to get to the actuator to either 'index the gears' or replace it altogether.

 

Pulled fuses 18 and 27 while running and that did not work. Letting it sit over night with the battery disconnected. Next will be a new orifice tube. Then I donno...

 

Disconnecting the battery overnight didn't do any good.

Connelyh posted in the thread below that if the orifice tube is clogged it could cause the warm driver's side as well.
http://forums.corvetteforum.com/show...AC+warm+driver

Guess I'll replace that along with the seal(s)behind the compressor where I have a slow leak.

Anyone else got any other suggestions?

 

If the orifice tube was clogged your pressures would not read normal.

 

So what do I look at next?

- Warm driver's side
- No AC codes
- Good AC pressure
- Pulled fuses 18 and 27
- Disconnected battery
- Can see the actuator moving when I turn the ****

 

Anyone?...Bueler....Bueler...

 

I simply can NOT run the air con. its sacriligous and I 've had the C-5 for 6 years!!!

 

You may be able to see the actuators moving but are the shafts that move the dampers moving also???

Check that out and see if that is the problem.

BC

 

I can see the actuator working against the vacuum diaphram and all the shafts are connected in between, or at least from what I could tell. I may need to remove more of the dash/cluster so I can get a bigger picture. It's got to be something with the dampers. the passenger side is blowing low 40's. I want to mark where the damper (that I can see) is when I turn the temp down to 60, disconnect the shaft and see if it moves further.

 

OK, I realized that the diaphram is just for the defrost, vent, floor and has nothing to do with the heat/cold. I took the gauge cluster out so I could get at the actuator better. When I turn the temp **** I can see the actuator turning the baffle so the question was whether it was turning it enough. After some cussing I was able to get the actuator out (without taking the dasj pad off like the Helms says to do). I could see that the baffle could not go any further CCW (Cold). I even moved the baffle back and forth by hand, made it go full CCW and took some temp readings. The driver's side was still ~15 degrees warmer than the passenger side.

There is a plastic rod connecting two arms that go inside the air box that do not move with the temp **** or the vent/defrost/floor settings. It cannot be moved by hand. I thought it may be the passenger's differential temp but turning the passenger temp **** did not make them move either so I'm wondering what they are.

So I don't know what to do next.

 

Well my temps are now 75 drivers, 60 passenger so I'm low on freon again. I'm going to fix the leak (at the rear of the compressor) and put a new orifice tube in while I have the system cracked open, pull a vacuum with this: http://www.harborfreight.com/cpi/cta...emnumber=92475 and recharge and see where I'm at then.

 

I was following your thread because I have a similar problem. I've only gotten as far as recahrging the freon (needed 10 lbs) and disconnecting the battery to reset the actuators.

Have you had any luck yet?

 

After recharging my system, the AC is now working but if I run the fans at max the temperature at the vent is only at 69-72 degrees. If I slow the fan down to half speed, the temperature drops to 50 degrees. The passenger is always cooler than the driver vents. I wonder if I need to add more R134. I'm just glad it's somewhat working. The heat wave has been brutal here in SoCal.

 

I have not yet done the orifice tube and gasket replacement followed by the evacuation and recharge. he AC has not been unbearable lately after doing the recharge. There is still a ~15 degree difference between the drivers side and passenger side. I am not too hopeful that fixing the leak and/or replacing the orifice tube is going to fix it because the passenger side still gets down to ~40 so the system appears to be performing up to par. I still think warm air is being mixed in on the drivers side somewhere. It does not appear from the drivers side temp actuator because I checked that out thoroughly (sp).

I am doing long tubes at the end of August and may wait until then to do the compressor seal replacement and orifice tube.

Very annoying. I bet there are many out there with the 15 degree differential but don't know it because the AC system is still performing adequately enough.

 

Just bought a used C5 with the same problem.

1. Added some 134A. Didn't help.

2. Disconnected battery overnite.....that reset the door!!!

3. Cars blows cold air ...both sides.

Hope this helps! These cars are awesome!!!!!!

 

I picked up a couple of things from the Service Manual. The first one is a Service Bulletin and the second is a diagnostic table for improper temperature control.

The Service Bulletin:
CJ2 HVAC DTCs B0361 , B0441 and Drivers Side AC Blows Warm - accumulator air automatic compressor condenser condition control display evaporator head inoperative temperature vent #PI01069 - (May 8, 2003)
CJ2 HVAC DTCs B0361, B0441 and Drivers Side AC Blows Warm - accumulator air automatic compressor condenser condition control display evaporator head inoperative temperature vent
.

When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.

Condition/Concern:
CJ2 may experience an HVAC control head that will not properly control air mix doors after a battery disconnect. The vehicle may have a temperature difference side to side and may set DTCs B0361 and/or B0441. A typical complaint may be that the right side cools down, but the left side is warm.

Recommendation/Instructions:
Air mix door mechanical linkage build variance or wear may cause a slight over travel condition of the door. Whenever battery power is interrupted from the HVAC control module, it will perform a recalibration of the actuators once reconnected. During recalibration, the HVAC control module will drive the actuators to their minimum and maximum travel extremes (5 and 250 counts). The module issues a travel command to 0 counts, but expects to see feedback slightly less as the door hits the cold stop in the case. The module will then calculate a travel range from this data and compare it to a calibrated range within the HVAC control module. If the actual travel range is not within the calibrated expected range, the actuator will be considered not calibrated and the DTC will set and the temp door bias toward warm is the DTC failure action.

An actual range below this limit suggests an obstruction (something stuck in the door limiting travel).

An actual range above this limit suggests an over travel condition (wear, damage foam seals, etc.).

The range fault code can only be detected following a check of the left air temperature actuator travel range. The left air temperature actuator travel range check can only be initiated by disrupting power to the HVAC control module (disconnecting the battery for 60 seconds) or with the scan tool.

If thorough diagnosis of the electrical system shows all electrical components to be ok, replacement of the HVAC control module with a 2001 or newer part number is required

If this has already been done, a reset/re-time the actuators internal feedback sensor to lag slightly behind the actual position can be performed. Open the actuator case and reset the output gear and sensor gear by only 1 gear tooth. This will allow a feedback of 4 counts when performing learn.

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms.

Diagnostic Table. This will not flow correctly in the post so will take some reading to decipher. The first line after the stated action is for Yes and the second line is for No.

Air Temperature Control Inoperative CJ2
Air Temperature Control Inoperative <<CJ2>> Step
Action
Value(s)
Yes
No

DEFINITION: Driver's side air temperature control is inoperative. No DTCs are set. The driver's side temperature control button is the master setting for both the LH and RH electric actuators. The following table will diagnose either of the following two conditions: (1) The driver's side temperature control button is adjusted and neither the LH or RH electric actuators respond accordingly. (2) The driver's side temperature control button is adjusted and only the RH electric actuator responds. LH actuator is inoperative.

1
Were you sent here from the HVAC System Check (CJ2)?
--
Go to Step 2
Go to HVAC System Check (CJ2)

2
Disconnect the LH electric actuator connector.
Turn the ignition switch to the ON position.
Use a DMM to measure the voltage between terminal 5 of the LH electric actuator connector and ground.
Is the voltage within the specified range?
10.0-14.0V
Go to Step 4
Go to Step 3

3
Check the HVAC MiniFuse® #18 for an open circuit.

Is the fuse open?
--
Go to Step 17
Go to Step 18

4
Connect the DMM between terminal 10 of the LH electric actuator connector and ground.
Turn the ignition switch to the ON position.
Measure the available voltage at terminal 10 of the LH electric actuator connector.
Is the voltage within the specified range?
4.0-6.0V
Go to Step 6
Go to Step 5

5
Locate and repair an open or a high resistance in CKT 1791 between the HVAC control head and the LH electric actuator connector.

Is the repair complete?
--
Go to HVAC System Check (CJ2)
--

6
Are both the LH and RH electric actuators inoperative when the driver's side temperature control is adjusted?
--
Go to Step 12
Go to Step 7

7
Connect the DMM between terminal 9 of the LH electric actuator connector and ground.
Turn the ignition switch to the ON position.
Measure the available voltage at terminal 9 of the LH electric actuator connector.
Is the voltage within the specified range?
4.0-6.0V
Go to Step 10
Go to Step 8

8
Backprobe the HVAC control head connector terminal C8 with the positive lead of the DMM.
Connect the negative lead of the DMM to ground.
Turn the ignition switch to the ON position.
Measure the available voltage at terminal C8 of the HVAC control head connector when it is connected to the HVAC control head module.
Is the voltage within the specified range?
4.0-6.0V
Go to Step 9
Go to Step 15

9
Locate and repair an open or high resistance in CKT 733.

Is the repair complete?
--
Go to HVAC System Check (CJ2)
--

10
Disconnect the HVAC control head connector.
Connect a fused jumper between terminal 5 and terminal 6 of the LH electric actuator connector.
Turn the ignition switch to the ON position.
Use a DMM to measure the voltage between terminal C7 of the HVAC control head connector and ground.
Is the voltage within the specified range?
10.0-14.0V
Go to Step 12
Go to Step 11

11
Locate and repair an open or high resistance in CKT 1199.

Is the repair complete?
--
Go to HVAC System Check (CJ2)
--

12
Turn the ignition switch to the OFF position.
Connect the DMM between terminal D1 of the HVAC control head connector and terminal 7 of the LH electric actuator connector.
Measure CKT 1798 for continuity between the HVAC control head connector and the LH electric actuator connector.
Is CKT 1798 continuous?
--
Go to Step 14
Go to Step 13

13
Locate and repair an open or a high resistance in CKT 1798.

Is the repair complete?
--
Go to HVAC System Check (CJ2)
--

14
Reconnect all of the components back to their respective connectors.
Connect the scan tool to the diagnostic link connector.
Turn the ignition switch to the ON position.
Select HVAC readout parameters on the scan tool.
Rotate the LH side temperature control **** between full hot and full cold.
Check for the LH MIX MTR POSITION REQUEST and the LH MIX MTR POSITION FEEDBACK signal on the scan tool.
Does the HVAC control head send a change in position request to the LH actuator but the LH actuator sends no feedback response to the HVAC control head?
--
Go to Step 16
Go to Step 15

15
Replace the HVAC control head.

Is the repair complete?
--
Go to HVAC System Check (CJ2)
--

16
Check for any poor connections.
Check for any binding conditions.
If OK, replace the LH electric actuator.
If through testing it was found that both electric actuators were inoperative, then replace both the LH and RH electric actuators.
Is the repair complete?
--
Go to HVAC System Check (CJ2)
--

17
Locate and repair a short to ground in CKT 41.

Is the repair complete?
--
Go to HVAC System Check (CJ2)
--

18
Locate and repair an open or a high resistance in CKT 41.

Is the repair complete?
--
Go to HVAC System Check (CJ2)
--

Bill

 

Just wanted to thank everybody who posted a suggestion or response to this thread. My car is going into the shop Monday and I'll post the results of what they find and correct.
This is the first mechanical problem I have encountered in 6+ years of C5 ownership. Wish the track records of the MB and BMW were so good!!!

Joel in Atlanta

 

Thanks for the detailed info Bill. It's nice to finally see that TSB about the indexing of the gears in the actuator in print.

I know that the problem is resolved for most people by either reseting or replacing the driver's side actuator or charging up the system. I have yanked the dash apart and physically taken the actuator off and held the flap in the full cold position and there was still a ~15 degree difference. So maybe my system is low, but I charged it up a few weeks ago and got the passenger side down to 42 degrees. The driver's side was still ~55. I can't say what the pressure looks like now as I know I have a small leak but there was a 13 degree difference when it was fully charged. It seems like there is something else that is allowing the airflow to go through the heater core to the drivers side.

The attached diagrams should help to visualize:

AC Baffling:
http://img3.freeimagehosting.net/ima...f9cf94036f.gif

AC Parts Explosion:
http://img3.freeimagehosting.net/ima...a183edc1c5.gif