Michael, you know way more about this stuff than i do. i figured i would toss that out, as it is supposed to help with relay lifespan (a $3 diode vs a $30 relay). but i dont think that the fan on my older stuff (or bikes) has a diode (not that i looked), so i bet you are right.
but if one was to be frying relays (like Mustang John was), it might be worthwhile.
Some heavy duty relays have a diode in them already. It helps reduce long term contact face errosion from arcing during the opening cycle. Some have a "leading" or "arcing" contact face before the main contact face just for the purpose of taking the erosion away from the main contact surface.
Some heavy duty relays have a diode in them already. It helps reduce long term contact face errosion from arcing during the opening cycle. Some have a "leading" or "arcing" contact face before the main contact face just for the purpose of taking the erosion away from the main contact surface.