My Heater isn't working!

[KlutZ__Man]

'97 Ranger w/4.0L engine.
The blower motor fan works, the A/C works, and I can change where the air comes from. Floor, defrost, vent, etc. I just can't change the tempurature. It's as if the tempurature is stuck on the coldest setting. I'm assuming that the heater core is OK since the heater hoses get hot and I can feel the heat through the plastic shroud inside the truck. The heat just won't come through the rest of the system. I have two theories.

1. Perhaps there is a damper that is stuck somewhere in the heater compartment. The one that is behind the glove compartment seems to work fine. Are there more dampers that work the heater?

2. I'm really just guessing on this one. There is sometimes a howling that comes from under the hood. I think that it's the water pump, since my engine temps are a little higher than they should be. Especially for this time of year, when my temps usually run a little cooler than they do in warmer weather. Could this be the cause of my problem? It seems to me that if the heater core is getting hot, then I should at least get warm air, even with a bad water pump.

I'm no mechanic, but I can usually fix something once I know what the problem is. I figure that I could easily throw a couple hundred dollars at this and still not fix the problem.

BTW, I already changed the coolant, radiator hoses, and thermostat. Which brings me to a third theory.

3. Maybe my heater hoses are bad.

[modification_inc]

check the linkage on the heat selector lever under the dash.

[baumbradleyl]

I am having the same problem, only mine was stuck on cool, then it switched and stuck on hot. I think it might be GEM module, but I am not sure. The trucks been stuck on hot for over a year now. - Same Truck as yours '97 4.0.

[KlutZ__Man]

Originally Posted by modification_inc

check the linkage on the heat selector lever under the dash.

The heat selector is electronic. There is no linkage. As far as I can tell, the switch is working properly.

I am having the same problem, only mine was stuck on cool, then it switched and stuck on hot.

To bad it doesn't change when the weather changes. Hehe!

[woolfpack]

I have a 93 Ranger with the same problem. All i can figure out is that outside air is coming into the truck heating system throught the outside air mixure vent. i can not find this vent at all. If the both of us can find this, i think we can fix both of them. Can you smell rain in your truck or hear alot of wind. If so we are in the same boat.

[KlutZ__Man]

As a matter of fact, I do hear a lot of wind. It sounds like it is coming from the windows or around the door seals. But, I would have never thought that it had anything to do with this problem.

[woolfpack]

Then you have the same problem i do. There is an outside air mix vent somewhere in the system. If either one of us can find this vent, I believe we can fix the problem. Besides, I am tired of freezing to death in my truck. It was only 2 degrees this morning.

[gerg]

This blend door fix worked on my 98 Ranger. Took longer to read the entire thread than to fix it! (about 40 minute fix) Hope this helps.

gerg

- If four out of five people SUFFER from diarrhea, does that mean that one enjoys it? -