[mjdwyer23]

Hi Folks-
Well, after a fun filled day of overheating on the way to the inspection lane, I am going over all of the engine compartment wiring, including the electric fans. Apparently, the fan was wired with two parallel 30 amp fuses (glass type) from the alternator. These fuses managed to get hot enough to melt to their fuse holder, the plastic cylinder kind. What type of fuse would be adequate to prevent this from happening again? Should I tap the power off of the battery instead of the alternator? Overheating sucks!

Also, under the dash I found a bundle of clipped wires that are gray, yellow, and black. Any leads?

Thanks!

 

[Guest]

Hi Folks-
Well, after a fun filled day of overheating on the way to the inspection lane, I am going over all of the engine compartment wiring, including the electric fans. Apparently, the fan was wired with two parallel 30 amp fuses (glass type) from the alternator. These fuses managed to get hot enough to melt to their fuse holder, the plastic cylinder kind. What type of fuse would be adequate to prevent this from happening again? Should I tap the power off of the battery instead of the alternator? Overheating sucks!

Also, under the dash I found a bundle of clipped wires that are gray, yellow, and black. Any leads?

Thanks!

I just fixed a problem like this on a dual fan setup. They had both fuses wired to a single 12 gauge wire. On top of that one of the relays was not operating. One of the fuse holders was replaced after the original melted, not very nice.

I bought 2 new 40 amp relays, 2 new 30 amp fuses, the newer style plug in type, and rewired the feeds direct to the battery. Problem solved.

Car has a 543 rat and these fans are the only thing that moves air, no fan on the motor, so they need to work!!!!

 

[mjdwyer23]

Nice, that's what I'll be doing, I picked up a new plug in style carrier and 30 amp fuse. Thanks!

 

[mjdwyer23]

New-style 30A fuse wired straight from the battery instead of 2 glass fuses from the alternator. I cut the old fuses out of their holders (they were melted that bad), it appears they were 30A 32V fuses. It's been a while since I took a circuits class, could these have been the wrong fuses? Thanks!

 

[mjdwyer23]

Do you think the fuses coming right off of the externally regulated alternator was the reason for their melting?

 

[1Fast7D]

Do you think the fuses coming right off of the externally regulated alternator was the reason for their melting?

One fan or two?

You are not supposed to wire anything extra right off the alternator. Use the horn relay buss bar for power to the fans.

Melting is caused by a poor connection which equals heat, and glass fuses and fuse holders are known for this with high current loads. Solder all connections and consider using newer style maxi fuses as they have more surface contact area. (only one if using one fan)

 

[mjdwyer23]

One fan -- I rewired it to the horn bus with a single 30a maxi fuse. Were the fuses in there the wrong ones (location aside)? Thanks!