Adding Ambient Temp Gauge to my 300SD. Questions.

[cuban8]

I picked up an instrument cluster from a 1989 420 SEL the other day and am thinking about using it in my 1983 300SD, in order to have an OAT temp gauge.

I would simply transfer over the SD instruments into the SEL cluster housing and use the temp display, which is a 4 wire (part number 126 542 02 27).

1. Can I just hook up a thermistor (listed in other threads) to the display, and then ground and 12 volts, or are there more components in the system than just the thermistor and the display?

2. Where do the wires go? (I have the harness that goes into the four wire plug)

* two browns (I assume these go to ground)
* green
* gray/blue
* purple/black

[LUVMBDiesels]

Put the gauge in the SD cluster.

the cluster in the later car is different.

you will also need to pull the wiring and sensor from the SEL.

Make sure that the display is clear. if there is black in the window the display is shot

[cuban8]

The temp. gauge will not fit in the SD cluster. There is no slot for it in my '83, maybe later SD cluster housings could accomodate it.

It's no problem because either cluster housing slides right into the hole in the dash.

The main issue for me is: "How do I hook up the wires?"

[cuban8]

Answer to my own question.

Found it in the MBZ Chassis and Body manual.

Brown-ground
Brown-sensor
Green-sensor
Purple/Black-12v
Grey/Blue-12v for backlighting