I believe most extinguishers as mentioned above are manually activated, not automatically. Besides, how hot does it get in your cab, in the summer? Does it sit in a full hot sun?

Craig

My '50 Chevy 3100 5 window, '62-235cu, 3:55 rear
My truck ....... Respect The Rust
If I'm not working on my truck, '65 m00stang or VW camper, I'm fishing with the wife or smoking Salmon.