sounds like one.. faulty bulbs or... the most biggest problem look inside the black peace were the bulb goes into some times the connections get rusty or corroded ? possable lift up all your carpet and follow your wires.. that what i had to do... i fixed my problem.. " new bulbs and bulb grease "

 

The thing is, I have custom taillights, so I know it's not the need for new bulbs. And it's only the Stoplight warning that comes on, not the Parking lights, so I don't think it's the fact of having different lights, otherwise both warnings would come on. I don't want to remove the warning system entirely since it has come in handy when my coolant level's been low.