Signal light problem

1997 Chev Venture with 155K
When the signal light is engaged it blinks very rapidly as if the light way burnt out.
However, it does stop and goes back to normal functioning?
Any suggestions?

You could have a bulb that's starting to go. The filliment occasionally loses contact but then makes contact after going over a bump or by vibrations. Or a connector or wire is faulty. Next time it starts to blink rapidly, check your turn signals to see if one is not working.

That may also be a sign of impending problems with the rear tail lights. My van did the exact same thing, and I ended up having problems with my brake lights and the whole 9 yards of problems associated with defective circuit boards. The problem disappeared when I replaced the boards. Also check for corrosion on the bulb base and inside the bulb sockets.