What are you trying to control and what is the current draw?
A horn relay. I suppose it would be continuous if I get road rage !!
The coil windings inside the relay that activates it likely only draws 1/3 amp, maybe an amp at most but unlikely. The contacts that close when the relay activates is what handles the higher amperage for say a Fan, Horns, convertible top or other high amperage accessory.
So, if your just using it to activate the relay you should be fine
I'm a bit baffled as to why you would use the MSD relay pack to control the horn relay
hope his is helping
