I have a problem with luke warm air coming from my heater. I just
recently found that I don't have vacuum at the heater core control
valve, so the valve is always closed (no water circulating in the
core). I manually opened the valve and now have heat. The vacuum line
is coming from the firewall. I assume I have a vacuum leak under the
dash somewhere. Does anyone have any suggestions where to start
troubleshooting and what to take apart under the dash? Thanks.
I had a similar setup on my 1987 Dodge 600SE years ago. The valve on
that car was NORMALLY OPEN, and the vaccuum would be applied only when
the controls are in RECIRC (i.e. MAX cool) to shut off the flow of hot
water to the heater.
Thus, I suspect that the problem is with the valve itself in that it
does not returen to it's normal position (probably rusted, etc).
Hope it helps,
Makes no sense, as Aarcuda said, you arent supposed to have vacuum there!!
If you had to manually open the valve and got heat I would assume the
valve is bad and not allowing it to open when the vacuum was off if you
got heat after you manually opened it. The most common problem with lack
of heat on that vehicle is a stuck open thermostat or a stuck blend air
door. Google on how to check fault codes by cycling the key and looking at
the check engine lite. If there is no code you may want to make sure that
the cable is not sliding in the control assembly as you move it from hot
You have to remove the control head from the dash leaving cable connected
and slide the control. If the outside cable housing is moving instead of the
steel wire in the housing you can bet the door is seized up
Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here.
All logos and trade names are the property of their respective owners.