That's ringing distant bells with me. I'm sure I answered a customer enquiry for them a few decades ago. Using a triac (which they would have to do for dimming) in that hot environment would be fraught with problems, like overheating and loss of dimming control. Base-down operation would probably be required for best chance of success.

Thats a novel idea, works just like the intermittent wipers in my old fiesta!