Outdoor Temp Display Repair
 

Hello everyone,

EFFECTS: 1989+ Outdoor Temp Display Units whose displays have seemed to 'turned off' but are undamaged.

I was in the middle of replacing my speedometer cable on my 190E when I decided to tear into the cluster and see if I could fix the temp display.

Mine worked when I first bought the car, then a few years later simply stopped. The backlight was on but no information was displayed.

I took it apart and found that the capacitor had leaked out. I went to RadioShack and sourced a replacement.

The capacitor is a 47uF 16V unit. I replaced it with a 47uF 35V unit. It was $1.50 or so.

http://i.imgur.com/GRhzcl.jpg
http://i.imgur.com/onYq8l.jpg
http://i.imgur.com/V7V4Ml.jpg
http://i.imgur.com/yvDUfl.jpg

great diy man! now i can fix my friend's haha any idea how to fix the backlight of it? also it should be the same for w124 right? and a capacitor rated at 16v works with a 35v one? or does it work even better?

Wanted to check if the unit can be pulled off the front of the cluster to clean the back of the display lens or not?

Thank you. When mine isn't blank it fluctuates all over the place, but never reads correctly.

If you don't mind, could you expand a little bit on how to remove it? I assume it won't come out just by itself, you have to pull the entire cluster, right? And where is the other end of that sensor wire located?

Almost forgot - how to determine polarity?

pull the cluster out, sensor wire is onto the display, and you need 2 phillips, if yours fluctuates, yours might be bad (the display) get one from ebay or the junkyard, their not that expensive

thanks for the info james.

a bit off topic.... but for the past couple of weeks have been trying to fix a broken lcd monitor which also suffers from leaky/bad capacitors :mad:


the temp display on my car works, however its way off, about 20F. the other day it was about 50F and it was showing 30-32F. does this mean that its time for a new temp sensor, or could it be something else?

I just wanted to say Congratulations, and nice job.

Without asking for anything else. :P :D

That has to feel good to take care of it that inexpensively, too. Big thumps up!

That's from a 1989 190E? Looked so different from mine, looked like they integrated all the electronics onto one chip (die) to save on component cost, wire bonded the die & encapsulated....to save on packaging cost. Very impressed that they already used that manufacturing technology back in 1989!

Here's a quick how-to on taking out the display unit:

This was performed on my 1993 190E's unit. I have an 1986 model year unit and its significantly larger and less integrated. I just assumed the 89+ models were when there was a change over. I saw pictures of units from 89 w126s and they looked like this one.

Evidently late w126, w124, w201 units all the boards and displays can be interchanged as indicated in this thread:
http://www.peachparts.com/shopforum/diesel-discussion/289232-exploring-vdo-outside-temperature-display-w124.html

If you car's display works but the temperature is inaccurate, you should replace the temp sensor at the front of the car, I think, in the case where the numbers fluctuate all over the sensor should be replaced as well:
http://www.peachparts.com/shopforum/tech-help/264842-outdoor-temperature-sensor-replacment.html

http://i.imgur.com/LRmPgl.jpg

1) Remove Cluster from Vehicle
2) Remove These Screws, to remove the unit.

http://i.imgur.com/QZegel.jpg

3) Remove The plastic connector surrounding this pin so you can fit it through the opening

http://i.imgur.com/Y9vEll.jpg

4) Remove the display from the cluster

http://i.imgur.com/QqIzrl.jpg

5) Remove these two screws, and then remove the cover

http://i.imgur.com/I4Vgyl.jpg

6) Removing these two screws will disconnect the LCD display from the driver board

http://i.imgur.com/4JDozl.jpg

7) Replace Capacitor. Remember the black heavy line indicates the location of the negative connection. Maintain this orientation when soldering in the new capacitor. When replacing capacitors, rule of thumb is maintain same storage rating, use same or high voltage rating.

http://i.imgur.com/GRhzcl.jpg
http://i.imgur.com/onYq8l.jpg
http://i.imgur.com/V7V4Ml.jpg
http://i.imgur.com/yvDUfl.jpg

you need a new temp sensor, that goes to your bumper.. resistors on yours are probably dying

thanks for the update.. and james regarding my question, doesn't matter about the voltage?

and yay i can replace my bulb now (hopefully the pins aren't soldered into the bulbs):)

yes, his temp sensor is probably bad. I have a link to an anlternative source rather than Meredes up in one of my above posts.

The bulb is indeed soldered to the PCB. I dont have a picture of it though. Its on the side thats not shown in all my pic. Youd see if if you tear it apart. Make sure all your connectors are plugged in before assuming its the bulb.

Regarding the capacitor, yes as long as the capacitance rating is the same (uF) you can install higher working voltage capacitors, never go lower though!

thanks for the info JD.

so, did the fix you mentioned in post#9 work? the one about the thermocouples : Fenwal #192-302LET-A01 or Thermometrics #EC95F302W ?

were you able to open up the sensor's metal casing and install one of the aforementioned thermocouples? or did you have to go to the dealer to pick up a new sensor?


take it easy

The reason I was checking on how to pull off the temperature displacy. Was I have a couple of white dots. I am not sure what caused them, but sometimes during the daylight. They can make a number a little hard to make out, but nothing big enough for me to want to pull the cluster for. As long as, it's working. I am not overly concerned about it!