Mercedes Ambient Temp Display in an 91 XJ/MJ Clock
 

Here's a quick writeup for the Benz temp indicator install in the 1991 XJ/MJ clock. The parts I used were a junkyard ambient temperature display module from a Mercedes Benz (Mid 80s - mid 90s Mercedes W124 models 300E, 300CE, etc., part number 124 542 0105), and the module and temp sensor wiring harnesses.

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Remove the plastic case from the temp module as it sits too deep behind the clock. Four screws and it slides right off. Then remove the top cover lens assembly from the clock. Carefully use a sharp utility to cut the plastic pins that hold the face on. The 1991 clock is the only clock that has sufficient space to mount things like this. Check GoJeep's site in the clock section for some info I sent him regarding the 1991 clock.

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Next break out the Dremel tool and start trimming. I had to cut a hole in the back for the module harness connector, and trim down then trim down the edges of LCD display to fit into the lower slot in the clock. After everything fits and clears okay, mount the LCD display (I used Liquid Steel and clamped it in to set overnight).

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Replace the clock face by "welding" it back on. Lightly touching the pin holes with a low wattage soldering iron. Wire everything up and do a smoke test on the workbench.

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Ready to mount in the MJ! Mount the temp sensor under the front bumper, run the harness thru the firewall into the dash clock cavity, and hook everything up. I used the power, dimmer, and ground wires conveniently located on the cigar lighter. Finished!

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