Dash heater problem

[dabrooks]

Mine is an Evans control and the center knob is the temperature control. When you turn the knob it controls a cable. The cable in mine was binding and would not fully close or open the heater hose valve. I twisted the knob a little too hard and broke it. I was able to order a new knob. I have since been able to free up the cable but I am careful not to twist on the knob to hard. You should be able to look under your hood a see the heater hoses and tell if the valve is or was controlled by a cable. The control unit in my dash was really easy to take out and work on. If I get a chance I will see if I can get some pictures to post for you.

[dabrooks]

This is the first time I've tried to post pictures. I have 3 pictures. The first one is the control unit mounted in the dash. The second one is the control valve under the hood controlled by the cable. The third one is the unit removed from the dash so you can see the back of the controls.

[La.Paul]

So it looks like the thermostat knob has electric wires coming from it, not a cable, but controls a device that activates a cable. I never could find a valve similar to the one you pictured, controlled by a cable, when I looked in engine compartment, and I only have one hose in that position, which is the hose they put the manual valve onto. It looks like there are 2 wires attached to the thermostat control, do you know if one controls heat and one the AC? My controls are mounted in a much larger panel, and I have not been able to figure out how to remove it. I'll try to get by there this weekend and take some pictures. Thanks.

[roy wohlsche]

Hi,
My heater is completely different. My heat is controlled by
a damper door on the under dash unit. I found out about this
on the www.densoheavyduty website. This is the service
manual for the system in my mh. I should have posted
this earlier. Sorry. I think I might have a loose cable
hookup. I'll check it soon as it is covered up in the storage
area.

Roy

[dabrooks]

Actually there are no wires hooked to the thermostat knob. If you look close at the third picture you will see the back of the knob has gear teeth that mesh with the other wheel with teeth. When you turn the knob it either pushes or pulls the cable. Yours may be completly different. I guess the manual cutoff they installed will work it will just be inconvient.

[La.Paul]

Ok, I see it now. Much bigger picture on my iPad then what I was getting on my laptop. If the thermostat knob goes to a cable that controls the valve in the heater hose, how does it control the AC temp? Does it just mix AC air with a little warm air if you have the main control set to an AC setting?

[dabrooks]

I have found in the a/c mode if you don't have the temp control all the way to the coldest setting the heater valve is not closed and the air is warm not at all closed. When you are in the heat mode the compressor is off so you can use the temp knob to get warmer air. To get the coldest air in a/c mode you put it in max a/c mode and run the fan on high. If you have determined that you have the Evans control I have the owners manual I can make you a copy of. I can scan it in or mail it. Feel free to call me 301-802-3174

[La.Paul]

I have posted some pics of my dash control panel.






I have not been able to remove the plastic moulding that wraps around everything. I was able to pry the upper edge back to connect a 12v wire to the accessory switch in order to turn on/off my onyx xm radio add on. When I remove the the 3 screws and try to pry the whole piece off, it feels like it might break, so I could not determine how to get the ac/heat control module out, as it is behind the moulding.





Here is a pic of the heater hose. As stated earlier, there is only one hose in front of engine compartment, but after looking more towards rear I think I see the return hose back there. It is covered with corrugated plastic and I had originally thought it was wiring or something else.

I have a call in to service manager to see exactly what the original mechanism was on the heat control, as I never did see any sort of cable connected valve on the heater hose.

Thanks for everyone's input.