Weird heater issue

[Morkable]

I have been searching all over the place for a solution to my problem. I also did a search on here, found some stuff, but not exactly like what i have going on

My truck heater for the most part works perfectly. Really good heat, you can adjust and it works great.... but for whatever reason, it will just suddenly start blowing cold air. It will do this for an undeteremined amount of time, sometimes 2 minutes, somtimes an hour or more. I cant seem to figure out a constant to try to trouble shoot... the only thing that seems to happen is that it seems to happen with I go through a pocket of colder air. Which is kinda leading me to think it is the computer that controls this... is this plausable?

the truck is a 07 f350 king ranch

Thanks for any help

 

[6speedsd]

Blend door maybe? I know they are prone to fail. Then again it could be the climate control itself.

Tried giving the core a good flush? Was having issues with mine this winter. Sometimes it would blow hot, then others it wouldn't heat up much. Flushed the core and washed the nastiest black water out you've ever seen. After that, works fine. May not be your issue, but it's an easy thing to do.

 

[Morkable]

I was reading your post on that. I am going to try that just based on the fact it cant hurt... but I am getting beautiful heat most of the time,, just it suddenly for no reason blows cold and I mean real cold.. then it will fix itself

 

[Morkable]

bump,, anyone else with a good idea?

 

[POWER-STRUCK]

does it have EATC? if so it could be the interior ambient temp. sensor acting up!
could even be a clogged heater core or low on coolant, in extremes a blown head gasket

 

[Morkable]

Yes it has he EATC. I am quite confident the head gaskets are good.. and about 90+% sure that the heater core is fine... I can sometimes go several hours in perfect comfort.. then all of a sudden it will start blowing cold air,,, and I mean real real cold air.

 

[Morkable]

I have another question... I am starting to really think it is the EATC, so I started looking, and there is a plethora of numbers that all look the same. Does anyone happen to know which is the right one?

My truck is a 2007 F350 King Ranch CC LB Dually

 

[Morkable]

bump

 

[Morkable]

I found a you tube video yesterday that showed how to do a diagnostic on the EATC. So I ran that last night. Of course no error codes. I am really frustrated now, well not as frustrated as my wife is. She is driving the truck to work every day and freezing her fingers and face off.

It seems the colder the temp the worse it gets, When the temp is warmer (say around 0 F) the heater works fine.

 

[Morkable]

Do you think it is possible it could have something to do with the outside temp sender?

 

[Morkable]

Well I put some cardboard in front of the grill to try to cut down on the cold hitting the sensor, see if that makes a difference. Nobody else has any other ideas to try? I cant beleive that I am the only one ever to have this problem

 

[Morkable]

Ok, well in my efforts to fix this I have been trying just about anything, and well I have stumbled on something. I put a peice of cardboard on the main part of the grill, and presto we have heat at highway speeds. It still cools down when she slows down, but not like before. So, I am thinking it is to do with the outside temp sender. Although I cant understand why this would be tied together, but it sure seems to be..... any thoughts?

 

[bad moose]

By the main part of the grill, do you mean blocking most of the radiator? What's the engine temp running? Possibly thermostats hanging open.

Sent from my DROID RAZR

 

[Josh@DirtyDiesels]

My KR was doing the same exact thing. Tapped on the a/c control panel and it started working for a few days. Problem solved with a new (well used, but working) control panel.

 

[Morkable]

I am fairly sure that the thermostat is good,, temp gauge dosent seem to change, which I would expect if the thermostat was sticking....

I was thinking it might be the control panel too,,, but I ran a diagnostic on it and it checked out fine,, that is when I came up with the idea of blocking the grill, thereby slightly eliminating the outside temperature sensor. What made me think of this was the fact that if the outside temp was above a certain level the heater would work perfect,, but drop below a certain level and nothing but cold cold air... and also there was the occasional wild swings in temperature occasionally. I am going to try to find one of these sensors and change it this weekend. It isnt a real expensive fix, so it is a good place to start I think

 

[Demon]

I have always blocked my rad in winter, on all my diesels. Stick cardboard between cac and rad.

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[kyle43335]

i have a automatic heater control unit for sale if you need it?

 

[Morkable]

I have always blocked my rad in winter, on all my diesels. Stick cardboard between cac and rad.

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The only reason I put cardboard on there was to protect the outside air temp sensor. My theory is that it is malfunctioning, therefore causing the heater to not work properly. The engine temp is fine without the cardboard. And until recently the heat was fine too. AND once the temp goes up to approx 0 F the heat works perfect.

I would recommend not putting the cardboard against your rad. This causes undue stress on your fan bearings. The fan is trying to suck air through the rad, and with the cardboard there it is then trying to suck itself through the rad.

 

[Morkable]

i have a automatic heater control unit for sale if you need it?

How much are you looking for? I might be interested

 

[Demon]

You don't actually believe that, do you?


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