help electrical problem!

If a ground is bad it will find a route wherever it can even back through the circuit. The fact that as you clean things it's getting better is a good sign that you're hot on it's trail. You wouldn't believe how whacked out my tail/brake lights were acting with just one bad socket ground. Once I touched that one bad ground with the jumper wire everything went straight. Did you try replacing bulbs? Like la4spd mentioned, there can be problems with them too.