2nd gen, heater always on ?

[carterdj]

Hi,

Which flap controls the heater in the car, seems like the hot air is always on. I guess when i switch it to cold, some flap somewhere should open to outside air (car has aircon but not connected)
Any ideas where it is ?

Thanks

Darren

[bhm1712]

I believe the flap to check is on the passenger side of the car sited just below the right hand vent on the cowl panel. With hot air selected this flap should be closed to prevent cold air coming in and allow hot to circulate into the cabin from the matrix area.

[G20BlazerTA]

Could it be a vacuum pipe problem ? Don't aircon cars have vacuum pipes (instead of cables) going from the heater control on dash down to the various flaps that control heat and air direction etc ? If aircon has been disconnected maybe someone cut and plugged the vacuum feed from engine up to heater control on dash.

[Davy J]

There is a vacuum pipe that needs to be connected on air con cars, I know as is like that on mine.

[bhm1712]

yes there is one main vacuum pipe which enters the firewall from behind the internal heater box assembly, and exits the firewall under the hood just next to the rubber grommet where the wiring harness for the AC exits. this should connect to the intake manifold or carb.

The vent selector switch is actually a vacuum switch, and from the back of that there is a network of vac pipes feeding the various vac diaphragms around the front end of the car.

[carterdj]

Thanks All,

Yes i recently put that flap thing back on, I sucked on the diaphram and the flap moved, so i just connected it back up. To be honest I am not sure there is a vacuum into the car !!! I always thought that it was engine heat making my car so hot, but last night the vents were hot as well. Will have to have a look to see if I can find where the pipe should go, the only thing is I think the flap is down now.
Just had a though, down maybe closed.

[bhm1712]

Yes down is closed so no fresh cool air gets into the box.

The standard vac pipe to the manifold or carb is black. Turn the engine on and put the blower on full. Change the vent setting from off to any other setting and you should hear quite audibly the sound of the fan changing as the flaps change position. Probably best to change it from off to defrost and feel for air blowing out of the window defrost vents. If no noise change and no air movement then it usually indicates no vacuum.

[carterdj]

Can't see a vacuum pipe that goes into the bulk head, has any one got a picture of where it should connect to ?

[bhm1712]

http://www.firebirdtransamparts.com/tec ... arness.htm

Picture 10 down. Left hand side and top of picture. There are 3 cables/pipes exiting the firewall. The middle one is the vac pipe for the A/C vents and it connected to the carb.

[bhm1712]

Did you ever get this one sorted?

Mine has a similar issue which im about to sort out. The flap on the inside of the car in the passenger foot well (you have to remove the top half of the internal heater box to see this flap) is always open and allowing hot air inside the cabin. There is a little plastic clip which connects to the flap and the actuator and mine has snapped so when the diaphragm actuator is pulling on the flap, its not actually pulling it closed so the fan on low speed is always blowing warm air into the cabin. Gets really hot especially on a warm day. Im going to remove the plastic clip because its only held onto the flap with a pin and try and araldite it back together - doubt you can buy them now