maverickks

First time post so please bear with me. I have a 97 C5 that the fan blower motor is starting to run when the digital control module is in the off position. It will also run when the car is turned off. I thought that it might be in the control module and it even ran when it was unplugged. This is a problem that just popped up and just happens from time to time. I also noticed that I could hear the compressor turn on but hot would blow out of the vents instead of cold, and this just started as the fan is coming on more often. I am looking for some help or suggestions that might fix this problem. :confused:

MarkSee5

Sorry to hear you're having this problem. Fortunately you came to the right place, because I had a similar problem a few weeks ago:
http://forums.corvetteforum.com/zerothread?id=320529

In my case it was the blower motor control module, part number 52479971. It sells for $140 through the dealer, or $70 plus shipping and handling through gmpartsdirect.com. It's not too difficult to install. The module is located on the passenger side, behind the kick panel and above the blower motor.

I'm assuming you have the dual zone auto climate option. If you tried disconnecting the digital control head unit and the fan is still running then chances are it's not the digital control head unit and probably the blower motor module.

I can check the service manual tonight and see what it says for troubleshooting this.

On the off chance it is the digital control head (part number 9356081), I have a brand new, never used one for $300 including shipping. They go for $899 plus tax through the dealer and $540 including shipping/handling through gmpartsdirect.com.

Mark

maverickks

Mark,

I do have the dual climate and thought of the control head unit and when I disconnected it the blower still ran. I will check with the voltmeter tonight and see if I get the same readings as you did for the blower motor module. Could you give me a little help on where it is located and what the part looks like? Also, since you have done this which is the correct fuse to pull so that I can continue to drive until I get the part? Thank you for the information and your help is greatly appreciated. I am so glad to be part of such a great forum!!!

Jeff :D :flag


[Modified by maverickks, 10:24 AM 7/8/2002]

MarkSee5

Jeff,

The fuse is located in the fuse box behind the passenger footwell kick panel. I think it's in the top right corner, 3rd from the right, 35 amp. The exact location is in your owner's manual.

With the kick panel removed, pull out the top black piece covering and you'll see the blower motor. Above that and close to the firewall is a black module with a connector going into it, and a connector going out of it into the blower motor.

I'll post the troubleshooting stuff from the service manual tonight. Good luck!

Mark

MarkSee5

Here's the troubleshooting info from the service manual. I think there are a couple typos in it because it didn't make sense when looking at the schematic.

Basically pin B is always hot, pin A is ground, and pin C is variable which controls the fan motor speed.


Blower Motor Always ON

1. Was the blower motor system check performed?

YES: Go to Step 2 | NO: Do system check

2. Disconnect the HVAC programmer module connector
Turn the ignition switch to the RUN position.
Is the blower motor on?

YES: Go to Step 3 | NO: Go to Step 4

3. Turn the ignition switch to the OFF position
Disconnect the blower motor control module connector.
Connect a test light between terminal C of the blower motor control module connector and a known good ground.
Does the test light illuminate?

YES: Go to Step 5 | NO: Go to Step 6

4. Replace the HVAC programmer module.
Is the replacement complete?

YES: recheck system operation

5. Connect a test light between terminal B of the HVAC progammer module connector and a known good ground. (NOTE: I think this is a typo. I think they mean the blower motor control module, not the HVAC programmer module. There is no terminal B on the HVAC progammer module, but there is on the blower motor control module).
Does the test light illuminate?

YES: Go to Step 6 (NOTE: Another typo. I think it should say Go to step 7) | NO: Go to step 5

6. Locate and repair a short to B+ in CKT 63.
Is the repair complete?

YES: Recheck system operation.

7. Replace the blower motor control module.
Is the replacement complete?

YES: Recheck system operation

You have to reconnect the battery and insert the blower motor fuse you pulled to do this troubleshooting.

Here's the pinout for the blower motor control module connector:

Pin Wire Color
---------------------------
A Black
B Red
C Tan
D -

--|----|---
( D C B A)
-----------


Mark


[Modified by MarkSee5, 9:25 PM 7/8/2002]


[Modified by MarkSee5, 9:28 PM 7/8/2002]


[Modified by MarkSee5, 9:30 PM 7/8/2002]


[Modified by MarkSee5, 9:50 PM 7/8/2002]

maverickks

Mark,

Thank you for the detailed information from the service manual. I am sure that with this I will be able to find the problem and get it fixed, and it will be much cheaper with the heads up on the gmpartsdirect.com. I called the local dealer and the part was $156 plus tax, so I know where I will be doing my shopping from now on. Thank you again for the help and I will post results after I do the troubleshooting.

Jeff

MarkSee5

Jeff,

No problem. Chances are if the fan is still running when you disconnect the HVAC control head it's the motor control module. I doubt you have a short if no-one has been messing with the wiring.

Be sure you know what part you need, because gmpartsdirect.com will not let you return a part that was special ordered. I learned this the hard way.

Mark

maverickks

Mark,

My luck never fails me. I connected the battery back up to run the troubleshooting on the system and the fan would not blow with the key off to save my life. I did check the pins and found B to be hot and I knew that when I unplugged the HVAC control module that the fan would stay running so therefore with the process of elimination, I have now removed the old blower control module to verify the part number and I am ordering it along with some other part with a savings of $110 with the shipping included. This is all thanks to you. You have been very helpful and I would like to say thanks. Someday maybe I can repay the favor. Oh, by the wa,y if you ever decide to sell your vette please let me know. My last vette was black, they are a pain to keep clean but I love the way the look. Thank you again for all your time and help. :D :seeya
Jeff :)