blend door
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Since you mention "manually", I assume you have the C68 electronic HVAC system…
The blend door position is controlled by the blend door motor (first two pictures borrowed from Agent 86's thread on replacing his heater core):
The rod in the white plastic button is what actually controls the position of the blend door:
You could pop the rod out of the white plastic piece, move the rod to the hottest position and then pop it back in. The blend door motor has a very high ratio gear train and it is impossible to move the lever by hand.
One way to see what is going on with the blend door is to take out the blower motor module in the evaporator and look in the opening. The blend door looks like this in the 90°F (hottest) position (that's the heater core on the left -- the evaporator is out of sight in the bottom left of the picture. The air comes from the blower motor, goes through the evaporator and makes a left turn and goes through the heater core):
The blend door position is controlled by the blend door motor (first two pictures borrowed from Agent 86's thread on replacing his heater core):
The rod in the white plastic button is what actually controls the position of the blend door:
You could pop the rod out of the white plastic piece, move the rod to the hottest position and then pop it back in. The blend door motor has a very high ratio gear train and it is impossible to move the lever by hand.
One way to see what is going on with the blend door is to take out the blower motor module in the evaporator and look in the opening. The blend door looks like this in the 90°F (hottest) position (that's the heater core on the left -- the evaporator is out of sight in the bottom left of the picture. The air comes from the blower motor, goes through the evaporator and makes a left turn and goes through the heater core):
Thread Starter
Racer
Joined: May 2012
Posts: 269
Likes: 0
Since you mention "manually", I assume you have the C68 electronic HVAC system…
The blend door position is controlled by the blend door motor (first two pictures borrowed from Agent 86's thread on replacing his heater core):
The rod in the white plastic button is what actually controls the position of the blend door:
You could pop the rod out of the white plastic piece, move the rod to the hottest position and then pop it back in. The blend door motor has a very high ratio gear train and it is impossible to move the lever by hand.
One way to see what is going on with the blend door is to take out the blower motor module in the evaporator and look in the opening. The blend door looks like this in the 90°F (hottest) position (that's the heater core on the left -- the evaporator is out of sight in the bottom left of the picture. The air comes from the blower motor, goes through the evaporator and makes a left turn and goes through the heater core):
The blend door position is controlled by the blend door motor (first two pictures borrowed from Agent 86's thread on replacing his heater core):
The rod in the white plastic button is what actually controls the position of the blend door:
You could pop the rod out of the white plastic piece, move the rod to the hottest position and then pop it back in. The blend door motor has a very high ratio gear train and it is impossible to move the lever by hand.
One way to see what is going on with the blend door is to take out the blower motor module in the evaporator and look in the opening. The blend door looks like this in the 90°F (hottest) position (that's the heater core on the left -- the evaporator is out of sight in the bottom left of the picture. The air comes from the blower motor, goes through the evaporator and makes a left turn and goes through the heater core):
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
The blend door motor is electric. It's controlled by the HVAC programmer, attached to the firewall above the accelerator pedal.
It's fairly common for the blend door motor resistors to burn up or cause the solder connection to go bad. When that happens the blend door goes to one extreme and stays there. The resistors are 140 ohms, 5%, 1 watt. They should be replaced with 2 watt resistors, same value. They are in the lower left corner of the PC board (note that the PC board is discolored by the heat):
It's fairly common for the blend door motor resistors to burn up or cause the solder connection to go bad. When that happens the blend door goes to one extreme and stays there. The resistors are 140 ohms, 5%, 1 watt. They should be replaced with 2 watt resistors, same value. They are in the lower left corner of the PC board (note that the PC board is discolored by the heat):
Thread Starter
Racer
Joined: May 2012
Posts: 269
Likes: 0
Since you mention "manually", I assume you have the C68 electronic HVAC system…
The blend door position is controlled by the blend door motor (first two pictures borrowed from Agent 86's thread on replacing his heater core):
The rod in the white plastic button is what actually controls the position of the blend door:
You could pop the rod out of the white plastic piece, move the rod to the hottest position and then pop it back in. The blend door motor has a very high ratio gear train and it is impossible to move the lever by hand.
One way to see what is going on with the blend door is to take out the blower motor module in the evaporator and look in the opening. The blend door looks like this in the 90°F (hottest) position (that's the heater core on the left -- the evaporator is out of sight in the bottom left of the picture. The air comes from the blower motor, goes through the evaporator and makes a left turn and goes through the heater core):
The blend door position is controlled by the blend door motor (first two pictures borrowed from Agent 86's thread on replacing his heater core):
The rod in the white plastic button is what actually controls the position of the blend door:
You could pop the rod out of the white plastic piece, move the rod to the hottest position and then pop it back in. The blend door motor has a very high ratio gear train and it is impossible to move the lever by hand.
One way to see what is going on with the blend door is to take out the blower motor module in the evaporator and look in the opening. The blend door looks like this in the 90°F (hottest) position (that's the heater core on the left -- the evaporator is out of sight in the bottom left of the picture. The air comes from the blower motor, goes through the evaporator and makes a left turn and goes through the heater core):
