Ambient Temperature sensor

[Oil Stain]

The Ambient Temperature sensor that's in the grill seems to be giving strange readings at times. I can see 66* then it might go 100*. My question is, does this sensor have any effect on the operation of the A/C or any other function of the truck in any way?

2012 Ram 3500 Longhorn

 

[Ram4Sam]

Doubtful......The A/C would use a sensor inside the cab for the tstat setting.....

Sam

 

[Vt Redneck]

The Ambient Temperature sensor that's in the grill seems to be giving strange readings at times. I can see 66* then it might go 100*. My question is, does this sensor have any effect on the operation of the A/C or any other function of the truck in any way?

2012 Ram 3500 Longhorn

If it didn't have any effect on anything, it would not be there in the first place. I have noticed on my 2013 that wherever it is, it is in a crappy place that is heavily affected by direct sunlight. As such, I have come out on 35 degree days after remote starting, to find my heated seats etc not turned on because the truck was reading ambient temps of 60 due to it being nice and sunny out. Dropped to actual ambient temp as you started driving. The engine software can also sometimes pull from the OEM's ambient temp sensor and this can have an effect on fueling decisions. Not sure if that is the case with our trucks or not. But it's certainly there for a purpose. Likely your wiring is chaffed somewhere or the sensor is just messed up itself.

 

[Kirwin]

The sensor on the 2013 and later models is in the drivers side mirror. I'm not sure where it is on the 2012 models.

 

[Oil Stain]

The sensor on the 2013 and later models is in the drivers side mirror. I'm not sure where it is on the 2012 models.

The sensor is located on the driver side. You must remove the grill. It's in between the air cooler and the headlight. I moved it a couple of inches towards the headlight. It seems possible that it could be getting heat from the radiator, air cooler and engine bay from how it's mounted.

I've never noticed this issue before, so somethings not right.

Moving it away from those open areas might help. I haven't driven the truck yet. It's also possible the sensor is flaky.

The reason I'm bringing this up is I would like to know if this sensor affects the rest of the truck and the PCM. I've started having some strange issues.

Like I was towing and the coolant was starting to get hot 217* and you can hear the Rad fan kick in and the temp would climb to 224* then go right down to 204*.

The next time this happened, at 226* the fan suddenly stopped and the temp zoomed toward 235*. I immediately pulled over and shut the truck off and restarted and the rad fan came back on and quickly cooled the engine down to 199*. That was scary.

 

[mwilson]

The Ambient Temperature sensor that's in the grill seems to be giving strange readings at times. I can see 66* then it might go 100*. My question is, does this sensor have any effect on the operation of the A/C or any other function of the truck in any way?

2012 Ram 3500 Longhorn

In general vehicles with high end automatic climate control systems use the ambient air temp in addition to interior temp and sun load sensors to calculate what output level is required from the heat / AC unit. Hoopty has several sensors for that purpose. Lower trim levels with manual heater controls don't need that input...

 

[Vt Redneck]

The sensor on the 2013 and later models is in the drivers side mirror. I'm not sure where it is on the 2012 models.

Thanks ... I was afraid of that, lol. Was thinking about relocating it somewhere more shady, but that may be more challenging than it's worth if I have to rewire all the way from the mirror. It does self correct after you start moving. Have seen temps well over 100 degrees after being parked in the sun all day, when actual ambient was max 86. Just annoying inbthe summer, more annoying in the winter when you want that seat and steering wheel heated before you get in ... nah, I'm not spoiled! :-laf

 

[jhenderson]

My truck threw a code while plowing this winter because the outside temp reading was much different than the intake temp. I think the OAT sensor was iced over because it was reading 70f while the actual was close to 0 degrees. I cleared it and it never came back. This would seem to indicate a connection between the temp sensor and the ECM.

 

[mwilson]

I would imagine the ECM involvement started when the outside air temp display stopped being part of an option package and comes with all trim levels.

I know the 06 doesn't care if the sender is there or not as to how it runs, an unfortunate accident involving Seth, Seth's truck, a snowstorm and a broken tow strap surgically removed my grill and the temp sensor w/harness...made no difference to the truck other than a constant -40 reading on the display. Ran it that way for a week until I repaired everything.