Projects: Engine Blower and Switch
When I initially installed the engine compartment blower, I simply wired it directly to the engine - whenever the ignition was energized, the blower would run. After reading somewhere that the blower wasn't rated for continuous-duty and using it that way could result in a fire, I decided to put it on a switch with an LED indicator light - since the blower can't always be heard above the diesel's racket.
Why do we have a blower? I guess it's the result of a "belt and suspenders" approach to cruising: Eliminate potential problems before they have a chance to occur. Our thinking was twofold: 1) Exhaust hot engine compartment air to reduce the liklihood of an overheated engine; 2) Lower engine compartment temperatures mean cooler temperatures belowdecks - an important consideration in the oftentimes hot and muggy Michigan summer.
Observations since install: An engine compartment operating temperature of about 92 degrees, even on hot, muggy days. No overheating problems. No noticeable temperature increase in the cabin due to engine heat.