Another heating question for a different verhicle


Old 02-13-04, 10:54 AM
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Another heating question for a different verhicle

The heat gave out in my 96 Ford Explorer. Thermostat replacement looks to be too much for me to handle with my small quantity of tools. But, when looking under the hood for mechanical controls, I found what looks like a vacuum line that goes to a contraption (maybe a solenoid) in line with one of the hoses going to the heater core. I see a small lever underneath that can be pivoted 90 degrees in one direction. Could this have something to do with the heat ? I'm wondering if the vacuum line going to the top of this thing , when removed, will call for heat all the time, or the other way around. I understand this will not fix the problem, but at the moment, I just need some heat. I'll look for a permenant fix later.

Something else I noticed, with the engine running and the heat on, the A/C compressor was cycling, similar to when it is starving for refrigerant, when the A/C is turned on. In the cab of the vehicle, the heat-a/c selector switch is rotated clock wise for heat. Counter clock wise for cooling, with the off position being in the 12 o'clock position. Why would the compressor even be on when there is no call for cooling ? Could it be that air from the heater coil, is being used to to fight air from the evaporator of the cooling system ? Just for kicks, I removed the dc from the compressor so that it would not cycle. Now I have some heat. It still doesn't feel as warm as I thought it should. With an HVAC analog thermometer stuck into the register, I read 110 degrees. But it sure doesn't feel like it. Maybe cause I was chilled to the bone at the time. And it was checked at mid day. The real test would be at night. Any way, the compressor should be connected to DC but not operate untill cooling is called for, correct ? Some one, help me out. What is going on with these Fords ?
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Old 02-13-04, 06:52 PM
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The vacuum device you are referring to is your heater control valve. Be sure that it functions when the heat is turned on. This could be your entire problem or not.There must be vacuum on that hose when the heater is turned on.
The A/C is commanded on during the heat process to reduce fogging. This is a dehumidifying function.
Hope this is helpful to ya,
Old 02-13-04, 07:36 PM
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Watch the lever and have the car running while someone moves the temperature control from hot to cold. It should move one direction for cold (closed) and the other direction (open) for hot.
Old 02-14-04, 10:51 PM
mike from nj
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now you know what f.o.r.d stands for,

not to contradict anyone, but on dodges, the opposite is true, vacuum applied shuts off the heater control valve(like with the a/c on) no vacuum applied is full heat, i thought this was true on all cars, as that would be the default---broken vacuum hose reverts to defrost mode and full heat---for safety. i could be wrong though.

how do both your heater hoses feel, very hot or lukewarm? does the temp gauge move off 'cold'?

you could also put a piece of cardboard in front of half your radiator as a very temporary 'fix' for a stuck open thermostat. always keep your eye on the temp gauge and take it out the first day that hits 50F.
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