Resistor pack on Aux fan?

[dbals]

What happens when the resistor pack fails?

My aux fan keeps blowing fuses. Should I replace the pack before replacing the entire fan.

[gale]

It's a 2-speed fan. The only time it runs on high is when the coolant temp trips the thermal switch on the side of the radiator, so I'm assuming you're talking about blowing fuses on low. It should run on low continuously when the a/c is on, so I'm assuming that's the mode it's in when it blows the fuse. The fact that it's drawing enough current to blow the fuse indicates the ballast resistor is good. It's rare that the ballast resistor fails in the shorted mode -- they usually blow in the open condition and the aux. fan wouldn't run at all in low in that case.

My bet is the fan isn't spinning freely. It's not easy to get penetrating oil into it but worth a try. Usually what happens is the permanent magnets come loose and bind the motor from turning at all. If that's the case, then it's sure to blow fuses.

Check my site for more info:

http://www.nmia.com/~dgnrg/page_2.htm