I have a 1997 Dodge Grand Caravan. When it gets humid or after a hard long rain and if we just opened an closed the rear hatch and we drive and step on the brake the gas gauge goes to empty. Also after closing the hatch the lights on the inside of the rear hatch are dimmer than they should. Also when we step on the brake and apply either the left or right turn signal the turn signal blinks much faster. What could be in the rear hatch to cause this? To me it sounds like a bad ground happening when it gets humid or wet. If I slam the rear hatch closed a couple of times this solves the problem, but I would like to know what causes the problem to begin with.