I am trying to retrofit an external temp display into my SD. I got the display and probe from a member here and pulled the wiring harness and display-compatible gauge housing from a junk yard car.

The problem I am having is that the unit only seems to power up ever 4 to 5 times I try it, and when it does power up it displays + 88.8*C most of the time with an occasional -27.0* or -37.0*. I think I have got it to display the correct temperature once. The back light seems to work fine. I have been testing it on the bench with a car battery as a power supply.

I have verified that my wiring harness does not have any breaks in it, and have tried re-soldering the unit with no success.

Is the unit dead or do I have another problem?


Thanks

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine