cant stop the heat

[3jeeps]

I replaced the seal in the heater box and adjusted bowden cable but the heat still enters when driving down the road with the controls in off position.anyone else with this problem, how do you fix it?

[Red78j10]

I have the same problem and I would love more than anything to find the answer. I am about to start craming Sh** into the vents.

[Bob Barry]

I've already stuffed the floor vent with napkins.

A more elegant solution would be to employ a vacuum-actuated heater shutoff valve from an early XJ Cherokee, which routes the water past the heater core and back to the engine (an AMC cooling setup requires water to flow through that hose for ordinary cooling).

Then adapt a vacuum switch like a QT E-drive switch for turning it on and off, or to make it more automatic, wire in a vacuum solenoid to be actuated by the A/C fan switch.

[Lindel]

To all with heat problems (from the heater vents, not engine heat! ;) ), be sure and check to see that the right vacuum hoses go to the right ports on the heater controls. The wife's 78 has two hoses swapped, and the only way to shut off the heat, is to set the funcion selector to heat! Off is floor vents, and the defroster works as advertised. I haven't fixed it yet because we figured out what the problem was, and it's not an issue at the moment (that'll change with winter, I'm sure :rolleyes: )

[Ralph]

The heater components themselves are not affected by vacuum; only the flap that directs air to the defroster vents.

The problem is probably an obstruction in the flap that allows heat to come in from the heater core compartment. That is, the flap can't completely close.

First line of action is to remove the heater blower motor and, by hand and when possible by vacuum cleaner w/narrow attachment, scoop out the leaves and debris that have accumulated in the chamber that is immediately left (toward the driver side) from the heater blower motor.

If that doesn't solve the problem, then remove the box holding the heater core itself, which also contains the flap in question. Once you've gone that far you can see if anything is broken or otherwise not quite right.

It's all very simple mechanical stuff, but there are a few screws to turn in order to get to it.