'98 M3, Ambient Air Temp sensor

[szumlins]

So I've done plenty of searching and reading in my Bentley, but I can't seem to find the thing. All the threads on here say behind the brake cooling duct, but it isn't there. The Bentley says in the "Right rear of the engine bay behind cold air cowl" which I can't seem to find either. Anyone with a '98 4 door M3 have a pic of the engine bay and where exactly this stupid thing is?

[ICTBMW]

its on the driver side brake duct area, your sensor/connector may be missing that might be why you don't see it. The wiring is there, brown/yellow wires. Check it again behind/below your driver headlight area and also the horn area.

http://bimmerforums.com/forum/showthread.php?t=286578&highlight=temp+sensor

[paul e]

You can see it easily... Get down on all 4s and look into the brake duct, driver side.. You should see a thin grey probe sticking into the duct from the right hand side as you are viewing it.. Sometimes it falls out.. In that case, pop out the fog light, and look into the opening.. Youll see the yellow backside of the thermocouple with wiring attached. If it fell out, it will be on the floor of that area behind the fog light.

[szumlins]

Thanks for the info guys...looks like the Bentley was wrong on this one.

Unfortunately, it looks like the plug is no longer there from the driver's headlight wiring harness, so I'll have to wire by hand or find a new plug. Anyone know where to get harness plugs?

Also, it looks like the brown/grey wire is + and the brown wire is ground in the manual, but mine has a brown/grey and a brown/orange...

Lastly, trying to wire up the new sensor via alligator clips yeilded nothing. Anyone know what the signal should be across the circuit to read a temp other than -35?

[ICTBMW]

I have a write up for this, but search function is not working right now. :rolleyes

Bascially, you can buy those disconnector at ACE Hardware and crimp the bare wire on the "spaded" side and the circular side will just slide over your sensor prong. It fits great! Remember to tape everything off with electrical tape.

Also, there is a delay in the reading, give it about 5-6 minutes for it to update. I used a cup of ice water to test its out.

[szumlins]

Alright, I got it working finally. Thanks for all the help guys. I soldered up a little extension and then stripped an old molex connector to grab the pins, then tied it all in together. Took a drive, let the car warm up and it works just peachy!