My wife called the other day telling me black smoke was coming from under the hood. The PO had a external fuse wired to the AC circuit. The fuse holder and wire melted.
Tonight I pulled the fan and tested it (hooked it up to 12V through a fuse). It ran for several minutes no issue.

What else could I be looking at.

__________________
84 300D 251K
87 190DT 281K - Sold
06 Ford Escape 172K
94 Ford Ranger 250K
99 Chevy Suburban 181K

vehicle??

Sorry,
84 300D

__________________
84 300D 251K
87 190DT 281K - Sold
06 Ford Escape 172K
94 Ford Ranger 250K
99 Chevy Suburban 181K

On that vehicle, the lack of a fuse of sufficient capacity is a know problem. That's why a separate shunt was installed. What size fuse was inside the shunt?

Your solution is to simply replace the shunt with the identical item and make sure it has the 30A fuse installed. If you can find the ceramic fuses, you'd be way ahead of the game. See if you can get a reading of the current draw when running the blower.........they tend to use more current as they get old.

Thanks, I think there used to be a 30A, however, its just a piece of charcoal now. I used a 15A for my test. The whole melting and burning event has me a little worried

__________________
84 300D 251K
87 190DT 281K - Sold
06 Ford Escape 172K
94 Ford Ranger 250K
99 Chevy Suburban 181K

It tends to build on itself. The fuse gets warm, then the plastic starts to soften, then the plastic gets closer to the wire, then the plastic starts to actually burn when it touches the wire. Sometimes the fuse is still good but the plastic is completely melted.

If you replace it with ceramic (not easy to find), the problem won't return.