"Heater" fan blows constantly
Thread Starter
Racer
Joined: Oct 2007
Posts: 270
Likes: 0
From: Chapel Hill NC
"Heater" fan blows constantly
The "heater" blower is on constantly.... only on the passengers left foot.
New fan console switches.
So, before beginning the troubleshooting process... can someone narrow down the cause>
Anytime the ignition is in the "on" position, the vent on the lower console passengers side is blowing.... where you would expect the heater to blow air at your feet.
I cannot get it to stop blowing, even when the fan speed switch is in the off position and the vent/heater switch is in the off position.
Where is my problem? (relay, switch, fuse, etc.)
(fell free to point me to an earlier thread that directly answers my question)
New fan console switches.
So, before beginning the troubleshooting process... can someone narrow down the cause>
Anytime the ignition is in the "on" position, the vent on the lower console passengers side is blowing.... where you would expect the heater to blow air at your feet.
I cannot get it to stop blowing, even when the fan speed switch is in the off position and the vent/heater switch is in the off position.
Where is my problem? (relay, switch, fuse, etc.)
(fell free to point me to an earlier thread that directly answers my question)
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
It is supposed to blow at all times...except when the control head is dialed to "OFF". If it works in that way, there is nothing wrong with the blower/switch. If the airflow is always out that left lower airduct, then there is something wrong with the vacuum distribution manifold (on the left side of the control head) and/or the servo/ducting system in your car.
Tech Contributor
Joined: Aug 1999
Posts: 14,379
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
Beginning in 1975, all GM cars and light trucks have the blower motor running at all times when the ignition is "on", even when the blower & selector switch is in the "off" position. This is to maintain a positive pressure and positive airflow in the passenger compartment following lawsuits brought for carbon monoxide poisoning - the blower keeps exhaust out of the passenger compartment even if you have an exhaust leak.
Lars
Lars
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
Beginning in 1975, all GM cars and light trucks have the blower motor running at all times when the ignition is "on", even when the blower & selector switch is in the "off" position. This is to maintain a positive pressure and positive airflow in the passenger compartment following lawsuits brought for carbon monoxide poisoning - the blower keeps exhaust out of the passenger compartment even if you have an exhaust leak.
Lars
Lars
Safety Car
Joined: Aug 2001
Posts: 4,883
Likes: 11
From: North Easton Mass
Le Mans Master
Joined: Oct 2007
Posts: 7,451
Likes: 974
From: RI, Now Franklin/Nashville TN
During the summer, I just pull the wiring harness from the second relay on the passenger side once you open the hood near where the hood seals close to the windshield-No motor blowing! Only works if you don't use the A/C in the summer. I also have a manual hot water shutoff in the heater hose to completely stop any heat coming into the passenger compartment from the engine in the summer as well. Between these two techniques, fresh insulation under the rugs, and a Dewitts Radiator, the treaded heat that most C3's are known for is completely solved with my car.
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