I have a wiring problem. At night with the lights on the temperature gauge needl start to flicker and the headlights and dash lights flicker then it quits and is alright and start doing it again and now the speedometer quit i got a new sensor for it and it worked for 1 day and quit again. it is a 1990 dodge w250 diesel. is there a common ground under the dash somewhere for the gauges or something. any ideas would help thankyou