Quick question...

Where is the exterior temperature sensor located? Is it the little rectangular looking box mounted immediately behind the grille?

Anyone had problems with it? Mine seems to be reading about 10 degrees hotter than it actually is outside and doesn't seem to change much outside of a 5 degree range.

Does that sensor control or link in to anything other than the dash display?

 

You should have 2 sensors mounted on that center post directly in front of the radiator. One, the rectangular box, is an impact serverity sensor for the SRS. And the temp sensor should be directly above this. The temp sensor is just for the drivers info and doesn't or at least I don't think it does, tie into any other system.

Bring your truck into the dealer and see what they say, but I believe they have a pretty large range for acceptable error so your probably S.O.L.

 

Probably right... I know it hasn't been this far off in the past so, I feel confident that there's an issue. I still have 5.5k miles on the warranty so, I have a bit of time to ensure that it's broken.

I was hoping that the sensor may have been caked in a bug or something that was inherently 'insulating' the sensor but, no such luck.

Thanks for the help... I really appreciate it.

 

Rock - I had to have my temp. sensor replace on my '04 at around 4K. It was reading about 10-15 degrees hotter than it should have.

 

Thanks for the information. It seemed to be right on this morning on my way in to work as I had loaded a weather site on my phone and was comparing it to my dash display.

The temp was shown to be 62 on the website... 63 on my truck. Doesn't get much more accurate than that.

Yesterday, though, it was about 72 and the truck was reading 83 and actually climbed to 85 on more than one occasion on the 22 mile trip home.

-RP-

 

I've noticed that if my truck sits out in direct sunlight for while the temp sensor seems to be less accurate, maybe as an effect of the sunlight shining on it.

 

That's the same way my sensor reacts when faced towards the sun. Facing the sun at 5:00pm, jump in, startup and it says 115' !!!! Although as soon as fan draws air across grille, it drops quickly, even more quickly once I start moving. It seems to take a while after that to become accurate.

 

RockPick i got the same problem that started after i removed the fan shrouder.

 

Mine is somewhat the same. If it sits for a while in the sun, it is way off, but it seems to be pretty accurate once I've driven around for a while.

 

Depending on how and where the temperature sensor is mounted, it is very easy for it to pick up radiant heat from the surrounding materials instead of JUST air temperature. If you look at temperatures on bank signs, they are almost always higher than actual because of this.

It is good to know that the sensor is in front of the grill though, as I thought the temperature sensor was tied in with the compass in the box around the rear view mirror............

 

Exactly... I expect that. Mine is problematic after driving for 20+ minutes down the interstate at highway speeds though. Hence, the reason I think it's fouling...

 

The first day I had mine I noticed it was 7 or so degrees hot all the time. I only now for sure when I see the temperature at my house and then go to the truck. After driving for some time Im not sure though, never had a thermometer to compare it to, or really looked for one.

They definatley are not to great though.

 

Some early 2004s and '05s were fixed with PCM recalibrations for incorrect/erratic temperature readings. My mom's 2005 Expedition did this (really badly, I might add - it'd read like -46 on a 101 degree day in the summer), and a PCM update fixed it.

 

I'm definitely an early 05' (bought new in Nov. 04') so, this may be my issue. I can't recall it ever doing this previously though... I'm thinking sensor - unless they reflashed me during the entire injector problem ordeal (which wouldn't make sense nor was it documented on my service ticket).

I need a few more 'hot' days to make more notes on this issue. I say that because it seems to have been pretty much 'dead on' over the past couple of 'cooler' days.

Quintin - does that sensor send data anywhere else other than to the dash? Does the PCM use that data or just display it?

 

Curious if you found out what the issue was, mine has been reading insanely high for several months. Noticed it after I was playing with a programmer. Highest was 125 on a 60 day... Occasionally it is dead on, then it goes off where ever it wants to, always higher than reality,