newbie and outside temp display - PeachParts Mercedes-Benz Forum

mbdad · #1 10-27-2002, 01:47 PM

I have finally purchased my first mb.
I love my car and I love the shopforum. Every post has helped me gain more knowledge and for that I thank each of you.

Here's my question:
I own a 93 190e 2.3. The outside temp display is the only item on the car that does not operate correctly. I have read all posts on the temp display and sensor, but I have not seen the following problem.
Every once in a while at startup the display works fine - but only for a few seconds - then its gone. This morning the display came alive. After remaing on for about a minute - it was gone. The temperature displayed each time is right on the money.

This was the longest period of time that the display was on. It has only come on about six times in the last two months. I did change the fuse, but no help.
Any thoughts?

jsmith · #2 10-27-2002, 02:26 PM

interesting, those are the exact symptoms on my car except mine will stay on for long periods of time after a change in weather. it's been on solid these past few days. i attribute it to a bad connector or faulty temp sensor unit behind the instrument cluster.

assuming it is a similar design to w124 - you can do a simple test by disconnecting the probe lead at the junction inside the fuse box and placing a 3k ohm load across the terminals leading back inside the car. if the display comes on then it's the probe that's faulty, otherwise you have to check further upstream which is basically the display unit behind the cluster.

i've gone so far as to replace the thermistor which didn't fix my problem. a new unit is about $200 - i'm not really that eager to replace mine yet...

sunil190e-1.8 · #3 10-27-2002, 03:43 PM

i think the problem may actually be a faulty bulb which lights up the temp. display.

i replaced mine and the outside temp. display is back to normal.

you will need to get ot the bulb from behind the instument cluster

-the bulb itself is a cheap item to replace.

good luck!

mbdad · #4 10-27-2002, 06:18 PM

Thank you for your replies.
The temp sensor does not connect to the fuse box on my car - the wire goes directly through the fire wall grommet.

The display lights up fine with instrument panel.

Do you think that I may have to pull instrment cluster?

I wish that it never came on - it's driving me nuts!!!! The sensor must be OK as well as the LCD.

cornrow · #5 10-30-2002, 01:25 PM

Mine is doing the same thing. At first I thought that it did not display at all, but today when I started the car it showed -36F until the buzzer turned off. Obviously this is not the correct temperature, but it means that the LCD is good. How can I find the temperature sensor? I don't understand how you people can trace these things - I look under the hood and there are so many wires and tubes going everywhere I can't figure out what is coming from where.

Ty

jsmith · #6 10-30-2002, 03:40 PM

the sensor should be next to the front license plate holder, the cable goes behind and underneath the bumper and runs along the fender wall in the engine compartment on the driver's side. it goes into the fuse box where it connects to the harness that goes back behind the instrument cluster.

cornrow · #7 10-30-2002, 04:10 PM

I'm having trouble finding it. Is it the little hole shown in this picture inset into where the license plate should be? Thanks a lot for your help

Ty

jsmith · #8 11-01-2002, 07:31 PM

-that's the hole.

-Sunil's outside temp display is an LED not an LCD (glows orange).

We still don't know how to fix it short of replacing the $200 display unit...

mbdad · #9 11-02-2002, 02:42 PM

sounds like the only way to fix it is to pull the dash and replace. I'm not comfortable with pulling the dash yet. Perhaps someday. And I'm not going to pay that kind of $ to know what the outside temp is.
I will fix it myself someday!