I got in my car yesterday and the AC fan wasn't running. I thought it was maybe a fuse under the hood or a relay so I swapped/inspected them but no good. I could hear the compressor start and stop when I hit the AC switch so I knew the air conditioning is working but still no air coming from the vents. I then closed the hood with some force and then the fan started working...sorta. It just didn't come on full high like it used to. Beats me, so I drove it today and the fan will put out just enough air you can feel it but not enough to get it cold in the car. The air coming out is cold but just no volume. I do have the dual climate control module and last week the display was dim so I re soldered the resisters and that worked great, thanks by the way to those who figured that one out, but now the fan motor doesn't seem to work. I don't think its related but who knows. I did happen to twist the left temp control **** trying to get it to do something and the fan cam on high just for a very brief moment but then went back off. I have played with the system in manual with the fan speed control switch and it indicates full speed on the display but the fan doesn't work. Any ideas would be appreciated.

 

I can't say on the blower not working, but on the blower working and air barely coming out of vents -- check the vacuum line that comes off the back of the intake (MAP sensor). If that comes loose, it will cause the air to not come out of the vents well.

Check your HVAC codes, some codes like out of range door actuators (B0361?) will cause the fan to not work properly because it doesn't know the status of the vents.

Some more info:
http://vette.tnreeds.com/actuator/actuator.htm

 

Hi, if your fan was working ok before you fixed the control head and is not now, it's obvious that the fix messed up something. Might be a good idea to send the control head to one of the guys that fix them all the time, and have experience with them. A bad relay won't work at all, and there isn't a relay for the fan, just a fan control module, and a bad fan module usually looses a speed or two, but will blow on one or two others. One item you can look at is maxi fuse #49 in the inst pan fuse box. That feeds power to the fan module. The module itself is behind the glove box, and gets its signal from the control head. In manual mode if you set the fan to high, it should blow on high, no matter what the actuators are doing, it may not come out where you want it, but it should be running.
Below is how to troubleshoot the Blower control Module. you have to remove the pass side lower inst panel insulator to access it. Step #26 is the acid test for the module
Good Luck
++++++++++++++++++++++++++++++++++++++++ ++++++++
Blower Motor Inoperative at Any Speed
Blower Motor Inoperative at any speed <<CJ2>> Step
Action
Value(s)
Yes
No

DEFINITION: Blower motor is inoperative at any selected speed.

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

2
Disconnect the blower motor control module connector.
Connect a DMM between terminal B of the blower motor control module connector and ground.
Measure the available voltage at terminal B of the blower motor control module connector.
Is the voltage within the specified values?
10.0-14.0V
Go to Step 4
Go to Step 3

3
Check the BLO MOT MaxiFuse® #49 for an open circuit.

Is the fuse open?
--
Go to Step 23
Go to Step 24

4
Connect the DMM between terminal A of the blower motor control module connector and ground.
Check CKT 150 for continuity to ground.
Is the resistance to ground less than the specified value?
0.5ohms
Go to Step 6
Go to Step 5

5
Locate and repair an open or a high resistance in CKT 150 between the blower motor control module connector and G202.

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

6
Disconnect the HVAC control head connector.
Connect a DMM between terminal C of the blower motor control module connector and terminal C11 of the HVAC control head connector.
Check CKT 63 for continuity between these two connectors.
Is the resistance between terminal C of the blower motor control module connector and terminal C11 of the HVAC control head connector less than the specified value?
0.5ohms
Go to Step 8
Go to Step 7

7
Locate and repair an open or a high resistance in CKT 63.

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

8
Connect the DMM between terminal C11 of the HVAC control head connector and ground.
Check CKT 63 for continuity to ground.
Is CKT 63 shorted to ground?
--
Go to Step 9
Go to Step 10

9
Locate and repair a short to ground in CKT 63.

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

10
Disconnect the blower motor connector.
Visually inspect the 2-wire (PURPLE and BLACK) jumper harness for damage.
Using a DMM, check the PURPLE and BLACK wires for continuity between the blower motor connector and the blower motor control module connector.
Is the 2-wire (PURPLE and BLACK) jumper harness in proper working condition?
--
Go to Step 12
Go to Step 11

11
Repair the 2-wire (PURPLE and BLACK) jumper harness as needed.

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

12
Connect a fused jumper wire between the blower motor control module connector terminal B and the blower motor terminal B.
Connect a fused jumper wire between the blower motor control module connector terminal A and the blower motor terminal A.
Does the blower motor operate normally?
--
Go to Step 14
Go to Step 13

13
Replace the blower motor.

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.
Depress the blower motor control button until the MAX blower position is reached.
Depress the blower motor control button until the MIN blower position is reached.
Does the scan tool read the appropriate blower motor speed?
--
Go to Step 15
Go to Step 16

15
Replace the blower motor control module .

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

16
Turn the ignition switch to the OFF position.
Remove the scan tool from the diagnostic link connector.
Disconnect the HVAC control head connector.
Connect a DMM between terminal C12 of the HVAC control head connector and ground.
Measure the available voltage at terminal C12 of the HVAC control head connector.
Is the voltage within the specified values?
10.0-14.0V
Go to Step 18
Go to Step 17

17
Locate and repair an open or high resistance in CKT 540.

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

18
Connect a DMM between terminal C5 of the HVAC control head connector and ground.
Turn the ignition switch to the ON position.
Measure the available voltage at terminal C5 of the HVAC control head connector.
Is the voltage within the specified values?
10.0-14.0V
Go to Step 20
Go to Step 19

19
Locate and repair an open or high resistance in CKT 41.

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

20
Disconnect the HVAC control head connector.
Connect a DMM between terminal C1 of the HVAC control head connector and ground.
Measure CKT 150 for continuity to ground.
Is the resistance to ground less than the specified value?
0.5ohms
Go to Step 22
Go to Step 21

21
Locate and repair an open or high resistance in CKT 150.

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

22
Replace the HVAC control head.

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

23
Disconnect the blower motor control module connector.
Disconnect the blower motor connector.
Replace the BLO MOT MaxiFuse® #49.
Does the BLO MOT MaxiFuse® #49 open immediately when installed?
--
Go to Step 25
Go to Step 26

24
Locate and repair an open or a high resistance in CKT 1342.

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

25
Locate and repair a short to ground in CKT 1342.

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

26
Reconnect the blower motor control module connector.
Blower motor connector still disconnected.
Replace the BLO MOT MaxiFuse® #49.
Turn the ignition switch to the ON position.
Press the HVAC mode button until FLOOR is displayed.
Press the fan control button until high speed is displayed.
Does the BLO MOT MaxiFuse® #49 open with the blower motor control module connected?
--
Go to Step 15
Go to Step 13

 

Thanks for the help all. I tore into it today and proceeded with the troubleshooting as suggested by "bestvettever" but everything checked out fine. I was getting power at the blower so I looked at the fan a little better. It would turn by hand ok, but I noticed some rusting around the base plate so I decided to inspect the bearings and took the base plate cover off. The bearing housing was full of crud....rust, and dust, and whatever. The brushes looked fine but they weren't moving smoothly in their housing so I cleaned everything up, lubed the base plate bearing, put the thing back together and now it works fine. I know I will have to eventually replace it cuz the bearing didn't look too good but maybe it'll last till winter when I have nothing to do.

 

Hi, good job, thanks for reporting back so that we can learn from it.