I had mine replaced instead of filling the hole and I don't have a light, mine showed a light and the code said what was wrong, they broke the glow plug off removing it and removed the rest with an easy out, installed the new one. this was 7 years ago, zero issues since. You have a factory installed block heater on the motor, the lead was originally tied to the dipstick so it wasn't hard to reach, if it falls off then it's not near as fun to find it. Plug the puppy in and you'll never have a hard start issue in the winter again, mine was a pain after the temp got down to below 20 degrees, repeated glow plug starts to further warm things didn't help much. A dealer may be able to disable the glow plug sender so you don't have the light.
