I have a 88 300CE that has the outside temp displayed on the dash. The temp displayed was reasonably accurate up until a few months ago. Now it reads about 10 - 15 degrees high. The LCD display is 1/3 black.

Is there an adjustment to trim the outside sensor or is the display the culprit?

Thanks
Alan

The outside temperature display on my '86 300 had problems with the display gradually getting black. The black started in the upper right corner and slowly spread across the right third of the display. When I finally replaced the display, it was only reading one digit. I purchased a used display on Ebay for about $40. The 'new' display had the 5-pin connector instead of the original 4-pin. There is a MB TSB out on how to wire in the new connector. It turned out to be pretty easy. Now I have a good display.

The accuracy problem is likely separate although, if the display can only give certain digits, that may give false reading. There is no trimmer adjustment in this system. The temperature sensor under the front bumper connects directly into the display module in the dash.

If my memory is right. The sensor is a temperature sensitive resistor or thermistor which has the resistance go up as temperature goes up. If you are getting high readings, the sensor may be bad or maybe there is a poor, high resistance connection in the wiring from the sensor to the module.

The cable from the sensor follows a winding path from the fender up to under the fuse box where there is a connector to wires which then go to the dash and the module. To reach that connector, you need to remove the fuse box. Talk about a dumb design! The PO of my car had a new sensor installed and they just cut the old cable up near the left front headlight and spliced in the cable from the new sensor. They taped it pretty good and it has worked for years.

If the sensor itself is going bad, there is a low cost replacement thermistor which you can buy at Radio Shack or probably any good electronics parts place. I don't recall the part number but you might find it in this forum with a search.

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1986 300E
1993 Volvo 940 Wagon
1984 Volvo 240 (daughter's)
1976 Dodge 1/2T pickup, gas hog

It sounds like the LCD display is the culprit...
My story: The display on my e320 was also reading the ambient temperature wrong a few months ago, the degree reading would come on at start-up for a few minutes then disappear. I thought it was the temp. sensor cable, replaced it and nothing. I then ran a resistor across the connector for the sensor underneath the fuse box and the display read ten degrees higher than what was recommended by fellow board members, which was 70F. So I bought a used LCD display, took out the cluster and replaced the old one. All good again...

You can try replacing the sensor or running that resistor, just my 0.02.

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1994|040|W124.036|E500
http://www.mbworld.org/forums/image....ine=1216527951

i recently bought the thermistor...don't have time right now to install.... i got the number on line... i bought two...shippng and handling were the killers .. i think the two were 12 dollars. parts were like 2 dollars each

I read at 136 degrees all the time... i really don't know how to install...so i am not in a big hurry

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1989 300ce 129k
( facelifted front,updated tail lights, lowered suspension,bilstein sports, lorinser front spoiler, MOMO steering wheel, remus exhaust,stainless steel brake lines). (Gone)

1997 s320 154k (what a ride). Sold with 179k miles. Replaced with Hyundai Equus

1994 e320 Cabriolet 108k



1972 280se 4.5 153k Owned for 12 yrs, sorry I sold it


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