I just purchased a 1983 300SD . The guages ant tach worked when I test drove it and works on the drive home . I had to remove the loaner battery when I got it home . I later installed a new battery and sarted it the car but but no guages, no tach, no turn signals. I is allmost like changine the battery made this happen ? All of the other electrical stuff works ( windows , heater fan, headlights ). All fuses are OK . Before I go through the wiring diagram , I wanted to know where to look first if this is a somewhat common problem . - Thanks