I want to make a switch/relay so I can circulate the coolant in my radix intercooler set up and run the electric fans. I currently have my FAL efans running off a nelson efan wiring harness.

I was thinking a switch mounted on the dash would probably be the easiest. Thoughts/suggestions? Where should I tap into the wiring at?

I would probably run the fans and intercooler for 15 minutes. I dont want to run it off the ignition because sometimes I listen to the radio while working/washing the truck.

 

I asked this a long time ago and nobody responded. It has been about a year and a half so, TTT is goes. LOL But I really need to do it.

How can it be done without messing up the efan relays. I think the fans would draw to much current and a relay would be needed. Should I just tap into the fuse block under the hood for a power source? Is that live all the time?

 

I would love to help but im trying to figure out what you want to do...

Do you want to turn on a pump with the vehicle off?
Do you want to turn on the fans with the truck off?

 

I want to run the fans and intercooler pump with the engine off.

 

Ok, easy enough.

For the fans simply tap into the wire running to the PCM.
The wire that you used to tap into the PCM wire needs to go to a switch.
the other prong on the switch needs to run to a ground.

When you activate your switch the fans will activate.

Go to a Local autoparts or Audio store and pickup a 5 prong relay.
You have two wires on your pump.

On the relay run wires from pin 86 & 30 to a ring connector. These wires will be hooked up to the fuseblock or where you connected your E-Fan harness for power.

Pin 87 will go to the power wire on the pump.
The other wire on the pump will go to a ground.

Pin 85 will be tied into the same switch that you used above for your fans.

I will draw a diagram to make this easier for you.

Derek

 

Get a relay that looks like this!

 

Only a year and a 1/4 J.....Shheeeesh! lmao. I can keep my intercooler pump running with the key on but my fans, no. That would be sweet to beable to run them too but I'd worry about the battery?

 

Even better if you had a temp switch/thermostat mounted in your resovor (sp) that trigger the fans and pump on above a certian temp, now that would be cool!!!

 

Thanks for the diagram Derek!!!

I have a few questions though...
1. The neslon efan harness has 3 relays (1 for 1/2 speed fans, full speed, and AC, i think). Does that mean there are multiple wires going into the PCM and I ahve to determine which one is full speed?

2. Do I need to ground the pump if is already operational? It turns on when the ignition is in the "on" position?

 

Well to activate the fans on high
It would require 2 switches total *Updated* schematic

One switch to ground out the PCM pin which would trigger the fans on LOW SPEED
one switch to send positive voltage to the AC comp. wire on the fan harness.

Trace back where your pump is being grounded. If it is a chassis ground then all you would need to do is tie into the positive from the pump to 87 on the relay.

Your harness works like this.

When the PCM pin is grounded (VIA the temp setting in the PCM) the fans turn on LOW
When the AC comp is activated AND the PCM has reached the set temp. setting the fans will come on HIGH This triggers with a + voltage
If the engine has not reached operating temp in the PCM and you turn on the AC one fan will come on HIGH
of course if the engine is not up to temp and the AC is off the fans will not activate.