126 outside temp display wiring diagram

[Biodiesel300TD]

Does anyone have a wiring diagram for the outside temp display and it's associated wiring for a 126 chassis. I am attemping to adapt the dispaly into my 123. There are 4 wire that go to the plug. 2 brown ground wires, a big black power wire, that I believe just lights up the display, and a black with red tracer. I don't know where that wire goes. If anyone knows where that wire goes or has a diagram it would be much appriciated.

[quaid]

Brown - Ground
Black/Voilet - Power
Grey/Blue - Illumination
Green and one of the browns go to the sensor.

I retrofitted one of these into my W126. Real handy to see if its freezing outside!

[Biodiesel300TD]

So I should be able to ground both brown wires, and give 12v to the other 2 and it should work, yes?

[pmckechnie]

This is from an 84 500SEL. See if the wire colors match.
Paul

[Biodiesel300TD]

That match my colors.

[Biodiesel300TD]

The display I pulled out of a junkyard car doesn't work. It display's *F. Will Celcius display work with the probe from the F display?

[tinypanzer]

Are you sure the module doesn't work, or do you just not like the Fahrenheit display?

I have a spare Fahrenheit module..... But, I would double check your wiring and test your probe. There's not a whole lot inside that temp module that can actually go wrong. It's one chip, and LCD and a backlight.

Use a meter to verify that the probe is working. Sometimes, because of where they are located (front license plate) they get crushed by feeble parking attempts, and either short out or open circuit.

-tp

[compu_85]

Could you take a picture of how the temps sensor should be mounted? The one on my car was just floating around behind the bumper when I got it.

-Jason

[E150GT]

Originally Posted by Biodiesel300TD

The display I pulled out of a junkyard car doesn't work. It display's *F. Will Celcius display work with the probe from the F display?

I have used both a celsius and farenheit display in my car and they both worked on the same sender. I got tired of celsius so I got a F from the junkyard.

[Biodiesel300TD]

Originally Posted by tinypanzer

Are you sure the module doesn't work, or do you just not like the Fahrenheit display?

I have a spare Fahrenheit module..... But, I would double check your wiring and test your probe. There's not a whole lot inside that temp module that can actually go wrong. It's one chip, and LCD and a backlight.

Use a meter to verify that the probe is working. Sometimes, because of where they are located (front license plate) they get crushed by feeble parking attempts, and either short out or open circuit.

-tp

The screen is all messed up. There is a big black spot in the middle of it. I've grounded the two brown wires, green wire it connected through to the probe, and given juice from a spare battery to the big black wire and the black/red wire. All I get is the backlight. And I can't see the display working at all.

How do you test the probe?

[tinypanzer]

Well, if the display is visibly damaged, as if the LCD has cracked and leaked its juice inside the glass, then it is done for.

Testing the probe is done with an ohmmeter. If the probe is NTC (negative temperature coefficient), which I *think* it is, then the resistance will go up as temperature goes down. If not, then the opposite is true. If you get no resistance (zero ohms) then the probe is shorted. If you get infinite ohms, then the probe is open (broken wire).

But it sounds like your display is trashed. Got a pic? If there's a big black blob in the display, then the LCD is cracked and the unit is history.

-tp

[Biodiesel300TD]

Originally Posted by tinypanzer

But it sounds like your display is trashed. Got a pic? If there's a big black blob in the display, then the LCD is cracked and the unit is history.

-tp

You hit the nail on the head. I got if for free so I'm not too worried. Ebay has them for about $20, so a replacement won't break the bank.

I will test the probe to make sure it's working as well.