Two fans, one truck

[n33k0]

Hi everybody,

My 1972 C10 has two fans mounted on the radiator, but only one of them works. The fan on the driver side of the radiator is hard-wired to a toggle switch in the cab and that controls when the fan is on or off (I always leave it on). It is mounted on the outside of the radiator (against the side of the radiator facing the grille), and it pulls air out of the engine bay. It seems to work just fine, the issue is with the other fan.

The other fan is mounted on the engine side of the radiator, and seems to pull air into the engine bay through the A/C condenser and radiator. It has a wiring harness that plugs into the back of the fan housing, with two wires coming out of it. One wire seems to run to the positive terminal on the battery, the other runs into the cab where the previous owner connected it to the B/U LPS fuse. This doesn't seem like the correct way to power the fan, can anybody enlighten me how to get the fan wired properly?

I noticed the temp gauge rising steadily while sitting in traffic, creeping close to 220*, that is when I looked under the hood and noticed the fan was not working. I replaced the 10amp B/U LPS fuse and it kept the fan running for about one minute, then the fuse blew and melted. I'm hoping the faulty fan is the cause of the temperature problem, and it obviously is not working properly wired the way it is currently.

Thanks for the help,
-Nick