Ambient Air Temp Sensor missing and AC is intermittent

33copper

New member
Hello, I have searched the forum and have not found the answer I am looking for. My T1N is an 05, long and high roof cargo. The AC worked well for years and now it will work one startup and then it won't on another. I have it at the mechanic now and they said the Ambient Air Temp Sensor is missing, from what I can see; it should be located on the front bumper, I looked and don't see it either. The next step it seems would be to trace the wire from the source to find the sensor or at least the connection so I can put on on. My van got a bad oil change two years ago and as a result has a new engine, I am wondering if they mechanic at the time put the temperature sensor in a different location but I am not able to find it. If someone could trace where the wire comes from for me on their van it would do me a huge favor.

The second part of the riddle is whether or not this sensor will fix the AC issue, but there is apparently a code right now calling out the Ambient Air Temp Sensor so the garage is focused on that as the cause of the intermittent AC issue stating that the two are related. Jury is still out.

Thanks,
Nick
 

Dougflas

DAD OWNER
It should be located behind the front license plate chrome bracket. It is snapped into place. It has 2 leads attached to it.
 

2004VannaWhite

Big White Box
If someone could trace where the wire comes from for me on their van it would do me a huge favor.

The second part of the riddle is whether or not this sensor will fix the AC issue, but there is apparently a code right now calling out the Ambient Air Temp Sensor so the garage is focused on that as the cause of the intermittent AC issue stating that the two are related. Jury is still out.

Thanks,
Nick
The wires run along the front beam of the chassis, under the AC condenser, merging into a larger wiring trunk at the end of the radiator (expansion tank). AFAIK, the outside temp sensor has nothing to do with the AC working or not, and only drives the display in the ODO.
 

33copper

New member
Thank you, I was skeptical about it having anything to do with the AC. My ODO temp display has been acting up (goes up with engine temp) so I'll fix it anyway once I find it. Maybe I can convince the mechanic that it doesn't have anything to do with the AC. It seems like if there isn't a code for it they won't even attempt these days. I'll update if they do find the culprit of the intermittent AC. I have read about a diverter valve in other threads being the culprit but my vents above the stereo blow warm just like the front vents. Just about to the point of adding a roof AC or something to cool the whole van better anyway.
 

2004VannaWhite

Big White Box
Thank you, I was skeptical about it having anything to do with the AC. My ODO temp display has been acting up (goes up with engine temp) so I'll fix it anyway once I find it. Maybe I can convince the mechanic that it doesn't have anything to do with the AC. It seems like if there isn't a code for it they won't even attempt these days. I'll update if they do find the culprit of the intermittent AC. I have read about a diverter valve in other threads being the culprit but my vents above the stereo blow warm just like the front vents. Just about to the point of adding a roof AC or something to cool the whole van better anyway.
Sounds like the outside air temp sensor is laying under the radiator/condenser, a common place to shove it when the interference fit pocket in the plate holder gets loose or broken! If the sensor was missing the ODO would show a fixed temp. The fact that it moves around at all tell me its still attached, but perhaps not in an ideal place for accuracy.

I am amused at some shops and their fear of AC systems, good luck getting it chilly!
 

33copper

New member
Sounds like the outside air temp sensor is laying under the radiator/condenser, a common place to shove it when the interference fit pocket in the plate holder gets loose or broken! If the sensor was missing the ODO would show a fixed temp. The fact that it moves around at all tell me its still attached, but perhaps not in an ideal place for accuracy.

I am amused at some shops and their fear of AC systems, good luck getting it chilly!
It's hard to find a real mechanic today.
 

Bobnoxious

Deplorable and adorable.
second part of the riddle is whether or not this sensor will fix the AC issue, but there is apparently a code right now calling out the Ambient Air Temp Sensor so the garage is focused on that as the cause of the intermittent AC issue stating that the two are related. Jury is still out.
Hey Nick, if the garage does not employ dealer level or equivalent diagnostic instruments, they will be spinning their wheels on your dime.
 

33copper

New member
Hey Nick, if the garage does not employ dealer level or equivalent diagnostic instruments, they will be spinning their wheels on your dime.
Thanks Bob. This is a new Garage for me, feeling them out; it's a big place that said they deal with sprinters but they aren't filling me with confidence. I have a freight liner dealer I may visit next but they are a ways away.
 

lindenengineering

Well-known member
Hello, I have searched the forum and have not found the answer I am looking for. My T1N is an 05, long and high roof cargo. The AC worked well for years and now it will work one startup and then it won't on another. I have it at the mechanic now and they said the Ambient Air Temp Sensor is missing, from what I can see; it should be located on the front bumper, I looked and don't see it either. The next step it seems would be to trace the wire from the source to find the sensor or at least the connection so I can put on on. My van got a bad oil change two years ago and as a result has a new engine, I am wondering if they mechanic at the time put the temperature sensor in a different location but I am not able to find it. If someone could trace where the wire comes from for me on their van it would do me a huge favor.

The second part of the riddle is whether or not this sensor will fix the AC issue, but there is apparently a code right now calling out the Ambient Air Temp Sensor so the garage is focused on that as the cause of the intermittent AC issue stating that the two are related. Jury is still out.

Thanks,
Nick
Nick a few corrections.
As posted previously the ambient air temp sensor mounted in the bumper cover is there for two reason
1) to give you outside air temp on the info screen
2) More importantly though, it also jives with the ambient air pressure sensor to compute an Air Density reading for the PCM.

There is/was a bulletin issued by Dodge in 2004 warning techs not to overlook it since it affected boost pressure performance in some situations.

As for the A/C; it runs almost independently from the engine.
No need for a jury to be out on this 'un !
Fixing the A/C is just like any other car of that era --dead simple!
For trained people that is I suppose !
BUT---As a tale of caution!
No You Tube grads or poseurs are tolerated by this system if you want it to blow cold at or below 33 Dgf !
Dennis
 

33copper

New member
Nick a few corrections.
As posted previously the ambient air temp sensor mounted in the bumper cover is there for two reason
1) to give you outside air temp on the info screen
2) More importantly though, it also jives with the ambient air pressure sensor to compute an Air Density reading for the PCM.

There is/was a bulletin issued by Dodge in 2004 warning techs not to overlook it since it affected boost pressure performance in some situations.

As for the A/C; it runs almost independently from the engine.
No need for a jury to be out on this 'un !
Fixing the A/C is just like any other car of that era --dead simple!
For trained people that is I suppose !
BUT---As a tale of caution!
No You Tube grads or poseurs are tolerated by this system if you want it to blow cold at or below 33 Dgf !
Dennis
Thank you Dennis. That gives me some ammo for tomorrow. I'll see if I can actually talk to the mechanic tomorrow. So far I don't have confidence. The AC blows very cold when it decides to be cold, unfortunately over half the time on startup it's like I don't have AC.
 

lindenengineering

Well-known member
Well the first thing is to check the charge 1.9 lbs.
Second i would be looking at the state of the pollen cabin filter and then the evaporator matrix for cleanliness.
I suppose I need to ask if the cooling fan is going active at about 300 to 325 psi on the high side! OR
If it works at all!!
Pull the binary switch socket off while its running to confirm!
The fan should automatically come on when the socket is pulled. .
Dennis
 

33copper

New member
I found a page (attached) in the manual that references the Ambient Temp Sensor and the Automatic Temperature Control Module as working together. I believe this is what the mechanic is alluding to as the possible AC issue. What do you all make of this reference from the manual? I'll have the van back tonight and have a Ambient temp sensor on order since its bad anyway, I just need to find it. I am thinking they didn't remove the license plate to look.
 

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hkpierce

'02 140 Hi BlueBlk Pass
The image above was misleading for me. The image shows the hole through the bumper fascia, but the mount location is actually in the license plate holder with a dedicated small hole that the sensor clips into. I found it easier to remove the plate holder to remount the sensor then to fight getting my arm between the fascia and frame - in other words, actually following instructions for once!

 
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lindenengineering

Well-known member
IF IF
The sensor is disconnected or compromised the fault will show as fault over CAN to the instrument panel!
Additionally the read out will go in the speedo info panel will go like this--------!
This can affect boost pressure read outs and performance . there is Dodge bulletin about it that came out in 2004.

As for the A/C system the system is straightforward just like any other commercial vehicle even big rigs ! The on and off and the pressure are just the same as a Peterbilt /Freightliner Class 8 . In fact fixing one is just the same a Pete/Freightliner !
Dennis
 

Bobnoxious

Deplorable and adorable.
Sprint guy calls it the "WITCHES HAT" and has been the topic of considerable discussion in other threads, with some members modifying the function with a switch.
 
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