Cabin Temp Regulation - Diesel Forum

lhrhodes · 01-14-2008, 02:55 PM

Anyone on the forum experiencing difficulty regulating temperature in the cabin of your new 6.4? I've got the lariat pkg in my 250 CC which includes dual climate controls. Sat morning was running the defrost and after getting nice and toasty in the cab, proceeded to lower the temp just a hair. Next thing I know, the defrost is blowing cold air. We're only talking a drop from 85 to 78 on the thermostat, which should not warrant as dramatic a change as I experienced. Anyone have similar issues?

Chrisb444e · 01-14-2008, 04:33 PM

ive never had that happen before, but maybe it was trying to compensate for the change in temp, by cooling down the cab, what happened when it reached 78 did it maintain? The only prob i have with mine and my 06 as well, is when the snowplow is on, it blocks the air to the ext. temp sensor it will read over 100deg. and a/c will come on when ambient temp is 20's. I cant belive they havent dealt with this its a real P.I.T.A. truck has snowplow prep...i cant be the only one plowing with a lariat

TurboForMyTurbo · 01-14-2008, 05:08 PM

did you have it set to "Auto" by any chance? ive read that the truck cab can be very warm, or think its very warm and if you drop the temp a little bit it will blow cold air. This only on the auto setting though. I just hit the button in the middle and have the arrows showing air blowing on my head and feet. Never had a cold air problem.

StanMI · 01-14-2008, 05:18 PM

Bama

78 degrees will feel like cool air to the touch. That feeling might be enhanced from being in the 85 degree temperature and feeling toasty for a time.

Did it feel OK after the temperature regulated ??

Chrisb444e · 01-14-2008, 05:29 PM

yes it is always on auto, but your right if you put to manual it gets better, but i have to keep cabin air temp set to around 90 to get good heat

lhrhodes · 01-14-2008, 05:58 PM

I did have the heat on auto. After feeling the cold air blowing, and I mean it was cold, I turned the heat completely OFF. Waited a few minutes and then switched onto manual and did not have any problems. It makes sense that the auto funtion might have been trying to regulate the temp from 85 to 78 by adding cool air. Thanks for the insight.

banshee069 · 01-16-2008, 03:09 PM

Mine does the same thing with my plow on. I called the dealer and there is a TSB on it for snow plows and winter front users. Right now there is no fix but the TSB says to run the heat on defrost mode or vent mode with the temp at 90. Then regulate the heat with the fan. I still have to open the windows or sunroof to get rid of the extra heat.
I thought about moving the external temp sensor from the pass side headlight to the bumper to see if it would help...

Chrisb444e · 01-18-2008, 08:59 AM

yeah its def. annoying this happened on my 06 as well, you would have figured they would have done something about it in the 08 along with all the other improvements. I htink the sensor would be blocked in the bumper as well.

lhrhodes · 01-22-2008, 12:57 PM

First and foremost, sorry to bump this up to the top of the new '08 powerstroke only forum, but since already here before the upgrade, thought I'd continue where we left off.

Well, it happened again, this time on the MANUAL setting. Not such a drastic temp change, but slowly ratcheting down in 1-2 degree increments every few minutes. By the time I got to 80, the heater was blowing cold air again, out the dash, out the defrost, out the floor, no matter where I directed the fan, I was getting cold air. Shut the heater off and restarted. What do you know, back to hot air again. I'm thinking I may have a faulty thermostat in the heating system. Thoughts?

banshee069 · 01-22-2008, 01:26 PM

I know it would still be blocked by th bumper but I thought maybe, it would not get as much heat from the engine compartment.