Well, I don't have copies of the thread... I'm not that organized. I can however re-type basically what I said back then as I remember.
The sensor for the 300e is located under the drivers side front fender behind the headlight. If you put the car on jackstands and get under there, you'll notice the feed wire running behind a rubber box with a single screw in the middle of it (at least I only remember one screw maybe there are 2) If you unscrew that box, it will come off and you'll expose the wire. It will feed into a silver colored metal end piece. Disconnect that so you have freed the wire from the car. Now you can get out from under the car and work on it.
The silver piece should just slip off the end of the wire to expose the sensor. The sensor is at the end of a plastic sleeve. The sensor is super small. I can't believe that this is all it is. The sensor basically looks like a tiny speck with two thin wires coming out of it. Also, as I remember, there is some white jelly/grease stuff all over it. That stuff is designed to keep the sensor from vibrating inside there and also to help transfer heat from the outside world to the sensor itself. Try to keep as much of that stuff on there as possible. Once you remove the sensor from the two leads and the sleeve, you'll notice that the sleeve has two sides to it. This is to keep the leads from touching one another and shorting out. Now that the feed wires are exposed and you can test the system as Barrie explained above. If you discover that the sensor is bad (and when you see it, you'll understand how realistic it is that it could easily go bad), carefully solder the new sensor in it's place. NOW, with the soldering iron, be super careful. This is a heat sensitive piece and it's easy to fry! only use a small amount of solder and only apply as much heat as is absolutely necessary. I bought two sensors (they're so cheap) so that incase I messed one up, I could easily discard it and try again. (Good thing I did, because I did mess the first one up. I think they cost $1.75 each) After the new sensor is in place, check the gauge on your dash and make sure it's working. Is it? Good. Now put it back together and go boast to your wife about how smart you are. That's what I always do.
As far as sensor locations on different cars, I don't know. I have heard that on some Benz's they're under the front license plate. Just put your car on jackstands and crawl under there. You'll find it. This is a super easy fix and it shouldn't take you too long. An hour at the most. I did mine a year ago and it's been working great ever since. If there's anything I've forgotten to explain, will someone please add it. Don't be afraid of this one. Have fun.
Kyle De Priest
1972 BMW R75/5 (Best there is)