When I turn on the headlights, the left blinker works fine but does not stay on.The right blinker stays on but doesn't blink. What could be the problem ? Thanks...

 

A few months ago I noticed the same thing. The Right blinker is iluminated, on the dash. Did you look at it from the outside, did you try the blinker, and look at the front and back? I didn't bother as I don't dive my car at night that often.
I figured it was something to do with the lights being on..

 

Start with replacing the bulb.

 

Check your ground wires. The little cheesy tab that goes into the rear lights breaks with age. It's amazing what all doesn't work right when those tabs break.

Bill

 

I've got another problem, now the signal lights, speedometer, rpm gauge are not working. Would I have to remove the dash to check the problem? Sorry for the noob questions. I'm trying to learn and do the work myself. Thanks...

 

try installing ( 2) heavy duty flashers. one goes at the fuse panel and the other one is under the passenger dash pad, at least on my 72'. had the same problem and replacing the flashers did the trick.

 

If you are a thin youngster you can lay down and pull the air vent out from under the drivers side and get to all the wires and stuff behind the instrument package. Us fat old folks get there by pulling the cluster out. 10 screws and two nuts and the steering column drops down and the speedo set comes out and I don't get stuck upside down under the dash. Yes, that was a bad day.

Bill