Indicator light

I have a dodge caravan 1999 it has 170000 km when I put my left or right indicator light on it does not come on but some times it come on and some time it does not what could be the problem
the next problem is when I start the van and put the heater on they is a loud noise when I put up the hood I saw theat the motor or pump would rotate and than stop making a loud screeching sound like as if the pump was getting stuck or jamed what could be the proble
the next pronblem is befor my oil galeval light used to come on but when checked the oil leval was ok even when I used to put new oil and filter the mechanic said it was a sensor proble and replaced it charging me 50bucks now I get the engine service required light coming on what could be the problem