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Topic: Dual Fans - Wiring??

in Forum: C3 Cooling and Heating Systems

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Dual Fans - Wiring?? (1/7)
8/2/08 3:24pm

Phill's Vette

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Apache Junction, AZ - USA

Vette(s):
1982,150K,Renegade CFI,Hooker Side Pipes,85 fuel pump,Bilsteins,HD suspension, Aluminum radiator, SharkBar/w 5-Point Restraints. 3:73 gears coming soon.

Joined: 10/15/2006
Posts: 285

Hello C3VR!
I have not been around in a while!
Anyway, I'm back with problems....
I just ordered an aluminum radiator with dual spal fans, the pull is rated at 35- 40 amps. Can I wire them in using the existing wiring or will I need to modify wiring with relay's etc.? I've heard that I will lose CFM output if the wiring is not rated correctly or worse - a fire.
I have modified the stock wiring to by-pass the thermal switch in the block with a switch mounted in the glove box. I live in Phoenix/Mesa AZ and I don't need to have them work automatically, so I want the switching to stay.
Any ideas and especially schematics would greatly help.
Thanks!
Phill's Vette2008-08-04 19:04:37

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Dual Fans - Wiring?? (2/7)
8/2/08 7:33pm

DaveM

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Flanders, NJ - USA

Vette(s):
1982 Black, ZZ4, Hooker Side Pipes, 3.55 Rear, Rebuilt & upgraded 700R4, All new suspension, brakes, & new Charcoal interior.

Joined: 1/27/2004
Posts: 2553

They come with everything you need, wires, relays, etc. The instructions are usually very clear. Why would you not want to use the temp. sensor?

I set mine up that way, the fans only come on when needed. I have a switch also that I can use when the AC is on because you need the air flow thru the AC condenser whenever the AC is on.

The kit should have everything you need.

Dave

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Dave's '82

Dual Fans - Wiring?? (3/7)
8/2/08 9:50pm

suncountry

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Moses Lake, WA - USA

Vette(s):
1976 L48 4-spd, Mahogany Metalic exterior, Buckskin interior 350ci/350hp, 3rd owner, fiberglass spring, 255/50-16's Torq-Thrust II

Joined: 4/16/2005
Posts: 2134

I ran mine through relays. I ran 2 12ga wires from the Bat + on the alternator to the 2 20 amp fuses and then on to the 2 relays, one for each fan. I pulled 12 volts off the 12ga leg to the coil (trigger) of the relay. Then ran the wire on the other side of the coil out to the temp switch in the radiator. I also branched off that wire to a switch under the dash for back-up.

If you look next to the brake booster you can see part of the fuse/relay block I made and mounted to the firewall.

http://img.photobucket.com/albums/v200/suncountry/Engine%20Replacement/EngineBay2.jpg

suncountry2008-08-02 22:01:35

Dual Fans - Wiring?? (4/7)
9/6/08 8:44am

wayne80
Former Member
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Canada

Vette(s):
1980 Dk. Claret T-Top

Joined: 8/23/2008
Posts: 12

I have 1980 L48 with AC. Next week I am replacing the rad and water pump. Is this the time to put in dual electric fans? Will they make that much difference. Seems like they add a lot of weight where weight is not needed.

Dual Fans - Wiring?? (5/7)
9/6/08 10:58am

lukesvette

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HOWELL, NJ - USA

Vette(s):
1979, Targa Blue (72 Color), Pace Car rear spoiler, L88 hood, Dark blue factory interior, 525HP 406, HD 700R4, 370 gears,Steeroids, composite rear spring, TT IIs wrapped in T/A Radials.

Joined: 5/18/2004
Posts: 6812

35A - 40A is on the high side. Double check the output of your alternator. I had a 40 amp fan on mine and it fried the stock alternator Dead

. I now run a 100A alt. with dual Flexolites that pull 27A.

As for the wiring, I think you would need at least 10 gauge wire. The instructions should tell you what you need. That's from battery. Powering up the relays from ignition should be ok with your current ignition feed.

This may be helpful if you don't have it:

http://www.spalusa.com/fans/automated/tech_sheets/FRH-185FH-195FH.pdf

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Dual Fans - Wiring?? (6/7)
9/7/08 10:04am

Phill's Vette

I ordered the wiring harness with all the needed connections, correct gauge wiring, relays etc. I also went ahead and upgraded the stock alternator (85amps) to a CS130 100amp. I will be installing the new harness this coming week.
Thanks for the help!

Dual Fans - Wiring?? (7/7)
9/7/08 4:49pm

suncountry

I realized today while I was under the hood that my power leads were 10ga and not 12ga. Fuses were 30A too. Got confused with some wiring I did recently on my MGB Shocked

You also need to go with a 100+ amp alternator.

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