Auxiliary fan install

[rokinn]

I'm getting around to installing an auxiliary electric fan and have a couple of questions as well as a general run by on the plan as a confidence builder.  I'll be using a fan out of a 91 XJ.  The 97+ is better I know but this is what I have for now.  I'm putting a 210 on/ 200 off switch in an HO thermostat housing.  I'm running the power through an SPDT relay (the ones that come from the renix relay panel under the hood).  I'll be using a 30 amp fuse between the battery and the relay and a 5 amp between the ignition and the relay.  I'll be using a rectifier diode IN5408 between the relay and the fan.  I may add a manual on switch from the cab but will start with just the temp switch for now.  This truck was never wired for a fan.  This is the plan I'm using. 

 

https://www.davebarton.com/pdf/coolingfandiagrams.pdf

 

This is the switch with added pigtail from Rodney Dickman parts.

 

http://rodneydickman.com/catalog/product_info.php?products_id=88

 

Questions:

1.  What is the best way to get power from the ignition switch?  Just run a wire in to the Ign slot in the fuse box or....? 

2.  What should the minimum gauge wire be from the battery to the relay?

3.  The switch pigtail has 16 ga wire.  Is that adequate?  The plan says to use 8-10 ga for ground but the switch is the ground. ?

 

Thanks for any input.

 

 

 

 

[omega_rugal]

5 hours ago, rokinn said:

1.  What is the best way to get power from the ignition switch?  Just run a wire in to the Ign slot in the fuse box or....? 

2.  What should the minimum gauge wire be from the battery to the relay?

3.  The switch pigtail has 16 ga wire.  Is that adequate?  The plan says to use 8-10 ga for ground but the switch is the ground. ?

 

1- the fusebox is a good place as any

 

2- 10 ga

 

3- put a solenoid, don´t run the fan through the switch

[Jeep Driver]

Remember-

 

The stat controls the temp in the engine/head.........coolant flows at 192/195. 

 

If you set your fan to come on late you are expecting your fan play catch up. 

 

Efans need to get ahead of the heat. On at 210 is too late.

 

 

 

The neg wire off the switch is nothing more than a trigger wire for the relay. 16g is fine.

The fan neg wire is straight to ground...........has nothing to do with the switch wire. 

 

Any ign source wire to trigger the relay..........tap into any wire under the hood is fine. 

 

12g or 10g wire to the fan.........my SPAL has 14g wire off the fan...........so your supply of 12g should be fine. Remember........you are only running 2-3' of pos wire and about 12" to 18" of ground wire. 

 

Fused supply and relay to fan will be right there at the battery/fan...............NONE of this wire needs to be run any further.

For the manual switch at the dash........ground at dash to switch then single ground wire to relay at ground trigger- same spade location as your temp switch connection.....basically you are overriding the temp switch circuit. 

[rokinn]

Thank you for the advice.  Much appreciated.