It may be a little more expensive than just the standard gage, but the TrailTech Vapor computer is something to check out. You can set two temp points that will trigger yellow and red warning lights which I think is a great safety measure. Good luck with it.

 

You would have to get the model that does not need a battery

E-mail:
Sales: sales@trailtech.net
Technical Support: tech_support@trailtech.net

http://trailtech.net/index.html

 

thanks !
i'll search on EBAY