Does anyone know how or know where I can get some info, maybe a DIY, on how to install the ambient temperature sensor on a 95 e320?

have you purchased a new one?

The ambient temp sensor is behind the licence place attached with one 8 or 10 mm retaining bolt. From there it snakes along the driver's fender to just under the fuse box (4 or 6 screws holding the fuse holders and assembly down). There is a connector under there that you'll have to disconnect and reconnect the new one.

On a side note, you have other options. The ambient temperature sensor is simply a 3300 ohm thermistor (resistor designed to maximize resistance changes with temperature) You can order these from www.mouser.com or www.digikey.com for less than $1 ea. Then you can simply snip the end of the OE temp sensor and attach the new thermistor. I drilled the reminants of the old thermistor out of the metal enclosure, soldered the new one onto the two wires, dumped some epoxy in the freshly cleaned out enclosure and stuck the new thermistor in that. Then bolted it back up under the license plate. Good as new.

Also, if you want to test to see if the temp sensor is really the fault, remove the fuse box (take the cover off, then take the ~6 screws out and lift it up) find the ambient temp sensor connector (following the wires from the sensor) and unplug the sensor. Use a 3.3k or 3k ohm resistor across the two pin connector and the gauge should read ~70F or so.

Good luck!

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Daily Driver: 02 E430 4MATIC
In the family: '03 E500 // '04 ML500 // 64 220SE

thanks a lot for the information! but what was everyone talking about that you needed to remove the instrument cluster and all that?

I believe on some models - perhaps the w201 (190e) the temp sensor was attached directly to the display behind the insturment cluster.

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Daily Driver: 02 E430 4MATIC
In the family: '03 E500 // '04 ML500 // 64 220SE

Ok now I have a problem. The head of the temp. sensor is too big to go through the little channel it has underneath the fusebox...Do I cut the sensor in half and re-connect it? Or do I cut the hole a little bigger?

There's a third choice - find out what's going on. Wrong part, wrong installation method - that shouldn't be.

how hard would it be to add one to a 83 126?

Tried the 3.3K Ohm resistor and nothing on the display with the car running. Anyone know where I can find an LED display?

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1993 400E, 256,000 miles (totaled)
1994 E420, 200,000+ miles
1995 E420, 201,000 miles

found some on ebay by searching w124 display. Be careful with part number and year of car though

Thanks. I found two on e-bay with the same part number (124 542 01 05), but the MB EPC shows a different part number for my car (A 000 542 72 27). One was $25 and the other $36. Maybe I should check the dealer and see what their price is too. It would put the risk on them if they gave me the wrong part.

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1993 400E, 256,000 miles (totaled)
1994 E420, 200,000+ miles
1995 E420, 201,000 miles

You need the 5-pin display, the extra pin is a speed sense input. All of the 5-pin 124 displays will fit/work on your car.

Oh, and go ahead on the dealer thing, the price that I was quoted was IIRC $390 for a 126 temp-display unit. Used makes some sense here.

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Gone to the dark side

- Jeff

Thanks.

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1993 400E, 256,000 miles (totaled)
1994 E420, 200,000+ miles
1995 E420, 201,000 miles