The Ford Barn - 55 Heater Box switch

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55 Heater Box switch

I am replacing the heater core in the wagon. In so doing I removed the heater box and came up with a couple of questions.

The switch/temperature control on the side of the heater box has two vacuum lines connected to it. One goes directly to the water control located on the intake manifold. The other was connected to the vacuum wiper and eventually ended up at the foot control for the windshield washers. I have replaced the vacuum wipers with electric so I do not need that vacuum line anymore and I am ignoring the windshield washer switch for now.

So, will only one vacuum line hooked up to the heater box switch be sufficient, and just cap the other port. Or do I need to run another vacuum line to pick up some vacuum from somewhere.

Second, looking at the picture of the switch itself, can it be cleaned up to work again? I'm not really sure how the thing works, just assumes that as it gets hot it shuts down the water going through the heater core.

Thanks
Jim

Re: 55 Heater Box switch

Yeah, you have got the vacuum operated heater control valve. That must have been a late '55. It was the standard control for the '56 model. My '55 has the mechanical control valve.
But, heres what you need. One hose runs from the thermostat valve on the intake manifiold to the heater control valve located in the heater plenum. Another hose runs from the heater control valve in the plenum to a plastic Tee fitting under the dash. The 2nd port of the Tee has a hose that runs thru the firewall and connects to the manifold vacuum line. The 3rd port of the Tee has a hose that connects to the vacuum wiper motor.
Since you have electric wipers now, you can eliminate the Tee altogether and run a new hose from the manifold vacuum line directly to the heater control valve in the heater plenum. You should notice a round cutout at the top of the cardboard heater register for the rubber hose to run thru.
The control valve itself can be rebuilt if it is not operating. (If you have heat coming out of the register in the summer when the valve is shut off via the mechanical cable to the heater control), is a good sign that it needs repair.
Concours parts does rebuild them, but it is very expensive.

Re: 55 Heater Box switch

Thanks, answer's my question about needing two vacuum lines. Hopefully I can clean up the switch I have, the rubber part seems to still be pliable and not cracked and it's minimal corrosion elsewhere, so I think I'm good.

thanks for the tip.