Where is the outside temp thermometer kept? That is what AMB means, right? Why is it that sometimes the AMB is severely off from realistic outside temperatures? It is sometimes 10-20 degrees lower than what it really is outside....

 

Mine is always right on, or within 3 degrees either side of the broadcast on the radio...

Yep, AMB...ambient (surrounding or background air temperature)...

DaveB might know where it is located...

 

within 3 degrees..

 

According to a local dealership, it is locate up front near the radiator, I think somewhere in front of it to keep from getting a false reading from the 'radiated' air. What I don't understand about your problem is how it reads LOWER!! I could see debris, etc, possibly causing a higher temp. One thought...in AZ you have colder nights and hotter days...when does this misreading occur...all the time or only in the morning, mid morning? If then, maybe something is bostructing the sensor and then insulating it...in effect acting like a cooler around it...

just a though....

 

Morning. This morning it was at least 80 degrees and it said 67. The climate control kicked the heat on. And I parked it outsdie last night.

 

2 things...

what was the temp outside last night? I mean air temp, not the car. If cold enough, I might take a while for the sensor to 'warm up' to the outside air...how long does the misread last usually?

also, 'the heat kicked on'? From what I understand, there is a sensor inside the cabin for the climate control and one outside for the AMB reading...your climate control may be totally out of whack, not just the AMB....

 

Yeah, the heat kicked on because it said the AMB was at 67 degrees and I had my sensor set for 75. So I saw it blowing at my feet- which usually means heat.

I have no clue how hot it was last night. I need to get a mercury thermometer and do some testing....

 

I think I got it now....the dial degrees are not the sensor trigger point, it is what temp you want the cabin to be...for instance, if I set mine for 65 (usually), this does not mean that the unit will kick on at 65, it means the unit will do whatever it needs to do to get to 65 (be it heat or cold). If you set yours for 75 but the car is only say 65 inside from sitting all night, the heat WILL kick on to achieve your goal of 75. This does not explain your AMB issue, but could cover your inside the cabin 'problem'...the inside temp is not controlled by the AMB sensor..

 

Yeah I knew the desired temp is what you set....I think I am just retarted. Maybe it was 67 degrees this morning.

 

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My 99SEL now is having this type of problem... It was first about -20 now it is reading about +20... anyone have a clue what to do to fix this?

 

Open your hood and look at the center support beam your latch is attached to in front of the radiator. The sensor is atached behind that beam. Follow the electric wire to find it. Disconnect the sensor, make sure the connections are clean. Clean the tip of the sensor off as well. Sometimes dirt on the sensor holds moisture after the morning due and gives a false reading.

The reason your AUTO climate control doesn't work correctly is because of that sensors incorrect AMB temp readings. The system uses all the sensors in the car to figure out what is needed to do inside the cabin.

Those sensors include:
Outside AMB temp.
Air Intake Temp
Cabin Temp
Sun Sensor - (The one in the passenger side defroster)
Discharge air temperature

 

This is your outside Temp sensor. Look next to your right fog light into the lower air intake.

 

If it is off that much, just take it to the dealer and have them diagnose/replace the sensor.

I park on a huge concrete slab and although the temp may be 75, the amb in the car says 88 due to the heat sink effect of sitting on a radiant slab of concrete. As soon as I drive off it will drop to the correct temp.
Mine is always within 1 degree of what I see on bill boards.

 

I've had many problems with the AMB temp getting out of whack. Sometimes it says 19, sometimes 25, sometimes it is correct, all the while the temp is 80, 90, or 100. I had emailed njmaxseltd about the problem over a year ago. I've unplugged, cleaned, and reattched the sensor only to experience the problems again later. The dealer replaced the AMB sensor one time and I again replaced it just recently, but to no avail. When I replaced it the last time last month, I even put table around the base of it, where it snaps in place with the harness, so that dirt/water couldn't get in there.

The dealer will need to see the problem in action; otherwise, don't bother going 'cause it will be a waste of time. I've been multiple times, even with it freaking out and the Service Manager going, "yep, it's messed up".

I've gone as far as checking the resistence values on some of the sensors in an attempt to diagnose the problem. I can say the old sensor's resistence checks out fine, so that leads me to believe the sensor is not the problem at all. I believe it to be one of the other sensors, although the in car sensor checks out fine, too, or it is a harness. Hell, it might even be the AC LCU.

I've been all over the ESM plus the built-in diagnostic mode of the AC. Everything checks out fine in diagnostic mode.

I'm still pondering what the problem may be. I have an order in for an in car sensor, the one near the steering wheel, in an attempt to see if that guy is causing the display/the LCU to act weird.

 

I found that my harness connectors on the back of the AC amplifier, the guy that accepts input from all sensors and all mode doors, was a bit loose, or not seated properly in the AC amplifier. I believe this may have attributed to my problems. The AC really kicks now, too, now that I fully seated the connectors.

The connectors do not snap or lock into place: the connectors look like the type found on aftermarket stereo units where you just push them in or pull them out without releasing a snap or lock. Both were definetely not seated properly, which probably translated to a broken connection or misread of incoming information.

Something to think about if your AC is flaky, but probably NOT the problem if you do not feel you get adequate cooling.