Blower motor relay
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Does your Corvette have a year? Why don't you tell us so we can better help you. If you have the electronic climate control where you select a digital temperature and blower speed, then you don't have a blower relay. Only the manual climate control has a relay and it is located just to the left (as the driver sees it) of the blower motor on the firewall.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Looking into the firewall (engine side) on the passenger side you see the blower motor and the a/c evaporator housing on the blowers right. On the top of the evaporator housing is the blower control module and two wiring harness plugs. The plug closest to the front of the car has a large red wire. Unplug that connector and measure the voltage on the large red wire pin. It should be the battery voltage and if it is zero, then the fusible link on that wire is blown and should be replaced. Behind the battery is a bolt with 8 red wires and the red wire from the blower control module is one of the wires on that bolt.
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Thread Starter
Instructor
Joined: Feb 2006
Posts: 101
Likes: 0
From: Bradenton Florida
I tested for power at the connector I have power at both pins. I didn't measure the volts though. Could the blower control module be bad itself. I had on good bad on a 86 that I used to own, it won't shut off the the blower and would kill the battery.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Yes you could have a defective blower control module. The only way I know of checking it easily is to replace it. You did jump 12v to the blower motor to prove it is ok didn't you? The motors have brushes that eventually wear out and the motor no longer runs.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Make sure the blower works by jumpering it to the battery and then check for voltage at the blower motor. At "1", it should have 4 volts on the Black/Red or Purple wire (or whatever isn't black at the Blower) and at "10", 12 volts. Also make sure the connector is good - too much draw or a voltage drop due to loose terminals can melt the wires. Then check the input signal from the Dash Controls to the Module which is on the Brown wire - though it may look black with age (and while you're at it, check the Black wire which is spliced into the Blower Motor ground and terminates on the frame providing a ground for the Module and the Blower Motor). That Dash input should have 2.5volts at "1" and something around 6 volts at "10". If theres nothing from the Dash, the Dash Controls aren't working. If the Module has the input, but nothing out and Power and Ground are good, the Module is bad.
Team Owner
Joined: Jan 2003
Posts: 20,292
Likes: 239
From: Summerland B.C. Canada
Melting Slicks
Joined: Jun 2005
Posts: 3,072
Likes: 83
From: Everyone needs something to believe in, I believe I'll have another beer. Wisconsin
I was having trouble with the blower working on my 91 with electronic control, seemed to work when it wanted but not when i did, altho lately seldom at all. While reading thru some threads i came across one that sounded similar to mine. it had to do with the wearing out of brushes in the blower motor. i went outside,started the car, and set the fan speed to 10. Of course it didn't start blowing because of some problem, i opened the hood and rapped on the blower motor with a pair of lineman's pliers and it started working
guess I'll be changing out the blower motor in the not to distant future.
guess I'll be changing out the blower motor in the not to distant future.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
I don't know - I hate hitting stuff and possibly breaking something when it's easier to just check for volts with a DVM. On the other hand, these old plastic connectors tend to break when you pull on the tab, so it probably doesn't matter.
Thread Starter
Instructor
Joined: Feb 2006
Posts: 101
Likes: 0
From: Bradenton Florida
Problem solved it was the blower control module. I tested for power I had power to it and not the blower, so I went to a junk yard and pulled 3 from some caddies with the electronic climate control. The first one didn't work but the second did and works great. I think the old one hasn't worked right for a while the air. So 16 dollars later and I have air again. Thanks for all the help.