Too Much Heat In The Cab...

[D2 Cat]

The truck is running real good. I've put about 130 miles on it since I've got it running. New GP's, OPS, return lines, rotors, front brakes, batteries, rebuilt injectors, cleaned the fuel monitor, new lines from FM, replaced driver door latch.

The heater is more heat then I can stand. I just replaced the blower high speed relay today. Prior to that fan worked on intermediate speeds only. Now it has an off position and gradually increases as dialed up, like it should.

The temperature control is what I need to check. How does it work? Where is it located (remember this is a '95)? Is there a bypass valve located up front by the firewall? What controls the temp.?

I've gotta get this fixed or I will have to disconnect the heater for the summer!!

 

[buddy]

Even with fan set to off, hot ambiant air is always piped into the truck if the temperature control is set to hot. If you set the temperature control to cold, ambiant air will still enter but not hot.

 

[D2 Cat]

When the temp. control is set to hot what is regulated to control the temp?

Last time I had it running it was on as cold as it would go and still pumping hot air. That's what I need to check.

Is there a mechanical valve, a vacuum controlled valve......?

 

[NVW]

There should be a door that opens and closes to control temp, I think on the 6.5 it is electrically activated.

 

[gulfyankee]

I am dealing with the same issue, first there was a cracked gear in the flap controller motor( just to the left of and behind the glovebox) now i think the head unit is acting goofy. ready to just replace that.

 

[D2 Cat]

How did you isolate it? Have you had the controller motor off to look at? How did you discover a cracked gear?

Is that the black "box" that doesn't look like it would be too difficult to get to once the glove box is removed?

 

[buddy]

MGW wrote a lot of good info in an older thread all about these components, search for posts by her with keywords for heater and such.

 

[gulfyankee]

yes took box off and opened it. there is a metal shaft that directly connects to the flap and a plastic gear that surrounds that shaft. that gear was cracked. used superglue to fix it

 

[D2 Cat]

I removed the relay off the top of the resistor pack. Replaced it and now all the heater functions work. Fan speeds all do what they are suppose to, temp control works, air direction control works...... one simple relay.

Thanks for the help.

Just a side note. A typical relay cost less then $7 (at O'Reilly's auto). The one that mounts on the metal piece with the two screws and slides onto it, and has the connection lock on it cost $20.

If you want to save the cost buy the less expensive relay and if you think it will rattle in there use a wire tie to anchor it to the screw you won't need now cause you can trash the metal bracket. I don't think the wiring is coming off of a breaker with 5 pins connected.

I mention this 'cause I have a container of various relays. I looked in there for one showing the same circuit as the one I removed. Found one, plugged it in, everything worked. I did go to town and buy the direct replacement, but only because I was in there for something else anyways, or I would have been satisfied with what I had.