Heating And Ventilation Issues

[Wez]

I am having problems with my heating system which I cannot find an answer to here or on the ford TIS disk. I have no recycle air facility. I have checked the vacuum at the engine and fan switch. There is air sucking at the pipe but seems weak. If you suck on the pipe which feeds the control module for the flap in the heater matrix housing you can hear the valve shut when you release the pipe. But this does not happen when everything is together the switch is operated. I have also checked the vacuum feed to the additional heater valve and solenoid. Again there is vacuum but feels weak and it would appear that this valve is always open to let the hot water to the matrix in the rear of the vehicle. Does anyone know how strong the vacuum needs to be to work this system? Has anyone else had this problem?

[JDF]

I am having problems with my heating system which I cannot find an answer to here or on the ford TIS disk. I have no recycle air facility. I have checked the vacuum at the engine and fan switch. There is air sucking at the pipe but seems weak. If you suck on the pipe which feeds the control module for the flap in the heater matrix housing you can hear the valve shut when you release the pipe. But this does not happen when everything is together the switch is operated. I have also checked the vacuum feed to the additional heater valve and solenoid. Again there is vacuum but feels weak and it would appear that this valve is always open to let the hot water to the matrix in the rear of the vehicle. Does anyone know how strong the vacuum needs to be to work this system? Has anyone else had this problem?

 

I also have this problem with the recycle air facility - fresh air okay, but when you switch to recycle you hear a vacuum noise but doesn't seem to shut off fresh air i.e. outside smells (smoke or fumes) fill the car.

 

Where are the vacuum pipes that you talk about???

 

J.

[Wez]

Depending on the year and model. Mine start from the manifold and feed to a tee-piece near the ABS modulator. From here one side feeds to a vacuum switch solinoid. This in turn feeds under the vehicle to just in front of the nearside wheel. It controls the valve for the rear heating. The other part of the tee-piece feeds through the bulkhead on the passenger side and to the fan/recycle switch. then from here to the heater matrix. As the pressure is equal troughout the systyem it would appear the pressure is low at the manifold. I notice that there is what appears to be a baffle/dampener here and there is a feed to something else, not sure what yet. I tested the valve at the matrix which opens and shuts the vent to the outside by sucking on the pipe at the fan/recycle switch. You can hear the valve shut when you release the vacuum. therefore I know that part works. There seem to be no leaks anywhere, as if you suck at the pipe by the manifold and hold the vacuum for a while it again holds. therefore I can only assume at this time that there is a blockage or leak towards the manifold. Difficult to test this bit. I have a vacuum guage but as I don't know what pressure to expect I can't fault find further.