Fuel Temperatue guage problem
I recently acquired a 1985 300D with 186k on it and have little history of the car as the previous owner had it for only a year. So far I have been able (with the help of several competent mechanics) to get it working satisfactorily. Thanks to this forum for valuable advice!! The previous owner had the fuel/temperature/oil guage replaced (was leaking oil) and they all work except that the turn signal or emergency flashers cause both the temperature and fuel guages to increase their readings whenever the green turn signal indicator flashes. When I turn on the headlights both of these guages increase dramatically at a constant rate and the seat belt indicator flashes.
I've checked to make sure all the bulbs were the recommended type(one of the rear turn signals wasn't), checked and tightened the grounds by headlight, trunk and in the dash by the steering column(it was loose). I also pulled the electrical connection off the back of the fuel/temp guage and reinserted it. Since the old oil pressure guage was leaking there was still some engine oil present which I tried to clean up as best I could without removing the instrument panel. None of these helped the situation. The lights and turn signals all work but I'm worried this problem may ruin the fuel/teperature guages.
I am suspect of the garage that installed the guage as they left the hot wire for the clock dangling and it created a dead short on that circuit until I reconnected it. That circuit is now OK. The previous owner said this problem was not present with the old guages. Any ideas are appreciated and if I need to pull the instrument panel is it a difficult task?