3dadd

My outside temperature sensor gauge was flicking on and off for a few weeks and has now gone out. I removed the instrument cluster and have removed the LCD temp module (part number 124 542 0105) and took it apart to clean the contacts. It will now come on and read 67 F and then shut off. (it's about 70 outside) . If there is no display on the LCD does this mean the temp cable is bad (the cable is near the front license plate). I have been reading the forums and some of the newer cars will still give a number when the cable is not working or disconnected. I also checked the cable connector under the fuse box. All looked OK.

The main question is : does it sound like the cable or LCD module?

battlecat714

It's probably the cable. If it was the display and your cable was fine, the reading would be off by like 10-15 degrees.

SUNILP

Check and see if the display comes on first when starting the car. If it does, then it's the cable. Replace the probe in front. The cable extends all the way to the fuse box.

AMG_Fred

Can you post on how to take apart the instrument cluster to get to the lcd screen? I need to replace my lcd and I don't know if I have to replace the cable or not.

battlecat714

Usually it's the cable thats the issue, but if you're having the same exact problem, then it's the screen. http://www.mercedesshop.com/Wikka/W124InstCluster. I suggest using the MB hooks to take it out instead of the hangers, those kinda scratched my leather , I have a set here if you wanna use them.

3dadd

I spent several hours trying to understand how the sensor works. Its really hard to see if the cable is the issue or LCD. The LCD comes apart fairly easily and looked OK. I cleaned all of the parts and can get it to come on for a while. Once it comes on it will usually go out after a few minutes. There are 2 Capacitor/resistor chips on it and my first guess would be when they get hot they go out. It always seems to show the correct temp when it pops on.

Has any one seen similar findings and fixed it by replacing the cable instead of the LCD.

AMG_Fred

Well if you know how to do this, I may take you up on this offer. And maybe if you even want to help... there is some dinner, my treat.

battlecat714

When I had the same issue, the LCD read 60F, on a 80 or 90 degree day on, something was obviously wrong, so I went under the fuse box, disconnected the cable and put a resistor instead, with the resistor, it should read around 70 or so, if not, bad display...it was ten degrees off... Went out, found a used display, put it on, connected the sensor back and voila, good as new.

I'd be more than glad to help you out. Plus a free dinner always sounds good.