I have a 1989 Corvette convertible with electronic temperature control.

The heater blower motor continues to run even when the ignition key is turned off.

The off button on the electronic heater control module also doesn't turn it off?

The only way to stop the blower motor is to unplug the wire harness to it.

Anybody else experiencing this problem?

sounds like a screwed up blower relay... I would start there.

I did a test today on the wiring system and found that the red wire to the blower motor control module on the heater housing engine side of the firewall is live all the time as it should be with heater controls off and ignition switch off. The remaining wires all showed no voltage as they should with that configuration.

The blower motor control module seems to be the problem as it is solid state and allows the blower motor to run even with everything turned off.

My understanding through viewing the wiring diagram is that the brown wire and the green/yellow wire are control wires to trigger the blower motor module off and on to control the blower motor.

I checked all of the other terminals on the heater control module in the dash and other connections and all appear to be fine.

On the electronic climate control I don't think there is a seperate relay for the blower motor as it appears to be a part of the solid state blower control module.

My Vette is a baby only 50,000 km.

Thanks for your response.

Jim

yes, I agree.

I have replaced that controller on my wifes 87. It caused her blower motor to not run past about speed 2, period...

I ended up replacing the motor at some point, but for a different reason - the bearing went!

I replaced the controller today and the fan will now turn off properly.

GM dealer price in Canada Delco Part $683.75. CDN

I purchased mine from a parts supplier AC Delco unit for $182.00 CDN

It pays to shop around.

Thanks for your response.

that price was SICK!!!!!!!

I don't remember it being that much! Or even close!!!

Strange, I've been messing with a window problem and was draining my battery occasionaly. At one point when the battery was way low the blower motor would run, ASR light came on, and a "tivking" comming from the dash boadr?? etc. Someone told me it was because the batt. was low and the relays were clicking??