I noticed that fuse #5 in the box inside the engine compartment was blown (the 40A one). Owners manual refers to it as protecting the "cooling fan" circuit.

I thought that engine was cooled via the belt, and my truck never overheats, so I was a bit confused. Maybe there's aux fan in there?

In any case, I replaced the fuse. But it keeps on blowing. One time, I just let the car idle, and sure enough, I hear something click and the fuse gets blown.

I'm wondering if it's something I really need to worry about, as long as I keep an eye on the coolant temp? It hasn't budged from normal level in all types of climates (including 100 degree heat, with A/C going full blast).

 

Sure, there is something to worry about, you have probably burned out one or both of your fans motors, depending on the madel and year of your truck.
This needs to be fixed quickly because the engine depends on the electric fans to help keep it cool as well as your a/c must have those fans running to perform.
So, check in front of your radiator, see if your fan/fans are able to be spun by hand, if not get them replaced before you over heat your engine.
Shout if you have any questions.

 

The fans come on when the a/c is started. Have someone start the truck with a good fuse in it. Look at the 2 fans in front of your radiator and see if they start and shut off. If it is just one, one may spin, one may not. From the dealer, you have to order as a pair. I remember someone sells them as single units. If you just want one, i can try to find it again.

Let us knw what you find.

 

I had that problem a few months ago and it can be as many things expensive to replace if done at the dealer, I found a good replacement from a yard on www.car-parts.com got both fans for around $50 plus s&h.

 

Thanks for the input. Yup, the fan is definitely rusted on, and does not spin. time for a new one. I only see one though..on the passenger side of the radiator.

It looks to be a pretty straightforward job, for DYI? Since the fuse is blowing, I'm assuming the electricals are functioning properly.

 

Here is a good scourse for a good guaranteed used fan,
http://www.roverlandparts.com/
Call them for a price.