Glow Plug light flashes off and on
 

My 1983 300SD a few months ago had a complete glow plug replacement including wires. Now, when running, the idiot light indicator flashes on and off randomly. When I first turn on the ignition, the glow plug light stays on until I hear the "click" then start the car fine...then the light starts flickering. I had thought it might be a bad connection, but then the light wouldn't necessarily stay on constantly when 1st turning on the ignition. Any ideas ?

The glowplug indicator light and the 'click' of the relay turning off should not coincide. The time the glow light stays on is determined by temperature whereas the relay is on a fixed schedule of around 40 seconds usually. Test it. Turn the key on. Watch the glow plug indicator light go out. Put your ear next to the relay and see if you can hear it click off after about 40 seconds from when it was turned on.
The flashing light is an indicator something is not right with the system. Why were the glowplug wires replaced. They rarely fail.