What amp relay for the cooling fan?

evintho

Registered User
I'm a Mustang guy (don't hate!) and I'm building an '89 Must with a turbocharged 4 cyl. My cooling system consists of an NPR I/C, Volvo closed system radiator and a '91 SC cooling fan. I'm about to wire up the fan. My question is what amperage relay do I need??

I've heard talk of relays needed as high as 90a due to the inrush current. However, I noticed this diagram that says a 30a relay is sufficient...............
http://www.sccoa.com/forums/attachment.php?attachmentid=6081

The above diagram has 2 wires from the fan. Mine is a high and low speed fan motor with 3 wires. Does the high speed require more amperage? Can you guys clarify this for me?

BTW, for anyone in Northern California needing parts there are no less than 4 SC's in the Windsor Pick-n-Pull yard right now.
 
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one than i know for sure is you can only run power to the low or high speed part of the motor at 1 TIME! if you run power to the hi and low at the same time it will fry in no time:rolleyes: just a little tip;)
 
The early 'birds used an integrated module.

I would think that a 30 amp relay for each of the low and high speed circuits, along with a 16 gauge (black) fusible link type fuse would be sufficient.
 

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the low side is around 35amp 12gauge, the high side is about 45amp 10gauge. radio shack sells both a 40 and 60 amp relay pretty cheap
 
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