Steer Safe and Safety Plus(horizontal shock type) are 2 of the most common. I have the Safety Plus installed on my Winnebago Sightseer 30B and it works pretty good to control wind sway from passing trucks and cross winds. It would also help in controlling your M/H in event of a tire blowout as well.
I think the heat exchanger you refer to is what is called water heater auxiliary MotorAid. This is contolled on my M/H by the dash heater controls where you set your heater temps for the cab area. There is a separate blower switch on my M/H to turn on the motoraid blower for the front and rear bedroom areas. Yours may or may not be similar-hope this helps