Relay for blower motor, where?
Thread Starter
Heel & Toe
Joined: May 2006
Posts: 20
Likes: 0
From: Oxelösund
Relay for blower motor, where?
1990 Corvette. My heater blower motor is running when it shouldn't. I guess it' s sticky relay causing this. Can anyone tell me where to find that relay? I have read service manuals without finding any useful information.
Thread Starter
Heel & Toe
Joined: May 2006
Posts: 20
Likes: 0
From: Oxelösund
I have searched for similar questions and just learnt about the blower control unit. I have also learnt that there may be a 5 amp fuse protecting the circuit sending motor information back to the control unit inside the car, and that a failure of that fuse may cause the blower to run at full speed all the time (I suppose the control unit inside the car then gets the impression that the returned voltage is too low and tries to speed up the fan).
Do you know about such a fuse, where it may be located?
My heater/ac control is working well, apart from this matter with the blower speed, so the data signalling to the blower control unit seems to be working.
Do you know about such a fuse, where it may be located?
My heater/ac control is working well, apart from this matter with the blower speed, so the data signalling to the blower control unit seems to be working.
Thread Starter
Heel & Toe
Joined: May 2006
Posts: 20
Likes: 0
From: Oxelösund
I think I found the 5 amp fuse, above the blower motor, under the cooling water filling tank. The fuse was ok and removing it made no difference at all to the performance of the blower motor, it ran and runs at full speed.
There is a code to get from the control panel, 10 - Blower PWM, which is said to give either value 0 (no voltage at all, zero volt) or 128 (14 volts). I will try to read out that value tomorrow (it's midnight here now). At least if it is zero, something must be wrong?
There is a code to get from the control panel, 10 - Blower PWM, which is said to give either value 0 (no voltage at all, zero volt) or 128 (14 volts). I will try to read out that value tomorrow (it's midnight here now). At least if it is zero, something must be wrong?
Safety Car
Joined: Jan 2004
Posts: 3,556
Likes: 12
The blower module is kaput , common fault.
As it is a "electronic " relay ,when faulty it allows power direct from the battery to the fan through a inline fusible link.
The 5A fuse I believe is on the control side so has no effect
As it is a "electronic " relay ,when faulty it allows power direct from the battery to the fan through a inline fusible link.
The 5A fuse I believe is on the control side so has no effect
Instructor
Joined: Jul 2007
Posts: 222
Likes: 0
From: Toronto(Don Mills) Ontario
Had the same trouble, all of a sudden, on my L86 Coupe(with C68), a few years back. A new blower module was the cure - the small fuse was still OK.
Thread Starter
Heel & Toe
Joined: May 2006
Posts: 20
Likes: 0
From: Oxelösund
I have come to the same conclusion myself and ordered a new controller module. I checked with GM here in Sweden first, they asked 450$, so I ordered it from Corvette Central for just under 70$ plus shipping and swedish taxes.
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