I recently took off my front bumber (2005 Convertible) to install a new horn . When I put it all back together, I noticed this item was left over with no obvious place to re-install it . I thought it was the outside temperature sensor, but I put it into a cup of warm water, and the temp did not change, so .... now I wonder exactly what it is?
It's located in the left front bumber and the wires appear to be bundled with the lights in that area. Any ideas ... please?

 

Turn your car on and give the thing a sharp rap. If your air bags deploy, you'll know what it is? (Just kidding.....don't do that.)

I'd just look through the various microfiches here:

http://www.realoem.com/bmw/select.do?kind=P&arch=0

 

Great idea! -- the second one anyway ... thanks for the link to the fiches!

 

It has the same measurements as the outside temperature sensor.
Is it located behind the bumper on the right (passenger-side), behind the lower grill?

That's the outside temperature sensor, can't really be anything else.

 

It's behind the bumper on the LEFT (driver-side), behind the lower grill. I found it in the mocrofisches listed as the "Evaporator temperature sensor" (A/C temp sensor?) but doesn't show where to re-install it.
http://www.realoem.com/bmw/showparts...=64&fg=40&hl=4

 

Sorry can't really help you there..

I can't help it, need to know the outcome. This sensor should be 'in the airstream of the air leaving the evaporator', which is part of the A/C..

Can hardly find anything on this particular sensor I'm afraid...

http://www.minicooperspeed.com/wp-co...emp-sensor.jpg

 

This temp. sensor snaps into a built in bracket on the backside of the lower bumper drivers side. This happened to me when I removed the bumper without help holding the bumper.

 

Great! Thank you! Now all I have to do is try and find the bracket without removing the entire bumper again ....

 

So this is a picture of the Outside Air Temp sensor on the passenger side, correct? Actually, I remember looking on the other side and could not find one there, so maybe this is mine on the driver's side!

 

I believe it fastens on the back of the lower grill. There is a couple fingers it snaps into.

 

Yes, it's on the drivers side.

 

Yes!

The outside temperature sensor kind of looks the same as the A/C thingy (both pointy), according to my book it should be in the left lower front bumper cover. That's the drivers side. (In Europe it's on the passengers side apparently)


I thought I was going crazy, it could not be the A/C evaporator temp sensor as this is inside the car...

Allright, found it in my Bentley-book. (640-09) This book covers your '05 convertible.

A/C Evaporator temperature sensor. This is no fun I tell you beforehand.

The instructions to remove:
This sensor is positioned inside the car. Your sensor clearly is not!

 

I agree -- all the evidence points to it being the outside air temperature sensot, but why, when I put it in hot water, I didn't see the temp gauge in the vehicle go up? I had the car running with the temp gauge on the dash (actually nav on this one) registering 36 degrees. It didn't budge. Maybe try a blow dryer? In any event. I'm going to try and look for the bracket it belongs on behind the grille.

 

Could it be that you broke it while taking the bumper off and jerked it out of its bracket???

 

I think this sensor is used by the computer to adjust things like your heating/cooling based on the outside temp. It is different from the sensor used to show the outside temp.

 

Some vehicles won't register a sudden increase in temp when the car is sitting still so as not to record the heat soak that occurs when the vehicle is shut down and restarted a few mins. later. An extended period above a certain speed is required to get an accurate reading. My dad's Buick did not have this and would register as high as 115 degrees even on a cool day if it was driven and restarted a few minutes later. A wide open blast of cold A/C was not a welcomed thing on a cool day!

 

It is infact the ambient air temp sensor (or outside temp sensor). It has a little semi circle clip it goes into on the left (drivers) side behind the grill. You can put it anywhere if the clip is broken, just zip tie it to something. It has no real function other than to tell you it's under 37 degrees so it might be icy. If you have automatic A/C it will also not run the a/c compressor if it's under 40 degrees in auto mode.
The sensor isn't that sensitive that it can notice instant changes in heat. If your air temp gauge changes temp at all, it's working.