Glow plug light illuminates intermittently with engine running

My car battery was dead again just now. I accidentally short-circuited the car with a different battery, and then I drove it into the driveway to charge it.

I noticed that the preheating light would occasionally come on. Sometimes 10 seconds, sometimes 3...

It probably doesn't have anything to do with the dead battery - the engine was running, after all...

I've found some threads on the topic of "glow plug light is on" - but in those cases, the engine wouldn't start... in my case, everything else seems "normal."

Roadrunner505 wrote:

I noticed that the preheating light sometimes came on.

Sometimes for 10 seconds, sometimes for 3...Did it stay on constantly? Then it's probably a glitch in the AI or some kind of wiring issue -> get the circuit diagram and start troubleshooting.

If it's blinking -> read the error memory.

No, it really shone brightly. It could really be any bridge - even in the dark, you can see that the lamp is glowing very faintly... damn.

Perhaps you've had a small water leak in your car .

and now, the copper worm is spreading due to the high humidity .

Okay, seriously now - The indicator light for the rear fog lights occasionally illuminates in my Passat's instrument cluster.

Specifically, whenever I notice moisture in the adapter at the AHK socket, I apply contact cleaner, and then it works fine again.