electrical question

I have a 2002 camaro which is having an electrical problem. The problem is the left turn siganl went out on me about 3 weeks ago and then 1 week ago the right turn signal and the running light in the front. The mechanic told me that it was a short and fixed it. Then today the right turn siganl does not again. I was driving it the other night and when I put the brake on and I had a serious voltage drop (I could see on voltage meter to 0V) the heater also went out on me for 2 seconds. Help

you could have a lose ground wire. Thats the first thing to check but Im not a electrition and dont know if that would burn out your lights.