69RavenConv 286 Report post Posted June 16, 2016 No problem, I haven't looked in a long time but I think a lot of the wire in the stock harness is 16 and 18 ga. Quote Share this post Link to post Share on other sites
69NC 21 Report post Posted June 17, 2016 The whole circuit for a 69 mustang is probably only 30 - 50 Amps I think the factory alternator was only 35 or 40 amps. I assume that you wired the power side of the fan relays directly to your battery, and are only using the fuse panel to switch them on? In which case you only need a few amps. The cotter pin will handle 100 amps or more, so if you get a short in your fan circuit, you could fry the wiring harness. Here is a simple example of how to wire up a fan. the orange wire in the diagram is the one that goes to the fuse panel, and it will only draw a few amps to activate the relay. Quote Share this post Link to post Share on other sites
RPM 1,190 Report post Posted June 17, 2016 Ya that's the single fan wiring diagram for my Spal, but I have the dual fan set up. I wired it like the diagram w/o the optional cooling fan override switch. Quote Share this post Link to post Share on other sites
69NC 21 Report post Posted June 18, 2016 Cool, than you only need a 5 or 10 amp fuse to protect it. I'd get rid of the cotter pin, it's one small accidental short away from a fire. Ya that's the single fan wiring diagram for my Spal, but I have the dual fan set up. I wired it like the diagram w/o the optional cooling fan override switch. Quote Share this post Link to post Share on other sites
RPM 1,190 Report post Posted June 18, 2016 Cool, than you only need a 5 or 10 amp fuse to protect it. I'd get rid of the cotter pin, it's one small accidental short away from a fire. I would get rid of it if it was mine. Not my post. Quote Share this post Link to post Share on other sites
69NC 21 Report post Posted June 19, 2016 I would get rid of it if it was mine. Not my post. Sorry Bob. I meant 69fstback, I think that's the original poster. Quote Share this post Link to post Share on other sites