View Full Version : Cooling Fan Help Needed
Randy's
06-15-2019, 04:54 PM
I hit a big milestone with my build today; first time starting the engine!. I had one small fuel leak at the filter but corrected that easily. After that, my Blueprint 347 with Holley Sniper EFI started right up. It ran rough for a few minutes as the Holley system "learned" and adjusted, then ran beautifully. However, I do have one issue that I can't seem to remedy. The cooling fan is not coming on. I have it wired to be controlled by the Sniper system and at 190 degrees, the Sniper system says that Fan 1 is "ON" so I know it is sending the signal. Obviously I have a wiring issue or a bad fan. My guess is the wiring. This is what I have done: The FFR wiring harness has three wires for the fan. A green wire, a blue wire and a ground wire. I wired the green wire to the positive wire coming from the fan motor. I did nothing with the FFR blue fan or ground wire; they are unused. Then I wired the ground wire coming from the fan motor to the light blue wire in the 10 pin Holley Sniper connector. What am i missing? As always, thanks for your help.
weendoggy
06-15-2019, 06:38 PM
The Holley Sniper can't control the "load" of a fan without using a relay. Look at this diagram http://www.weendoggy.com/wiring.htm#diagrams under Automatic or Manual override controlled relay and you'll see what's needed. The Sending Unit in this case would be your ECU trigger wire (which would be a ground circuit) to energize the relay.
Not sure on how may fan wires you have coming from the fan but most have two, a hot and ground lead. That's all you need unless you're using a PWM fan. To check your fan, connect the ground to ground and the hot to the battery or ignition hot and it should spin. If that's good, you'll need to wire the fan accordingly as in the diagram. If your green wire is a battery hot, that goes to #30 and the blue if ignition ON would go to #86. The black isn't really needed if it's a ground. The fan HOT lead would go to #87 and the Holley Sniper trigger wire would go to #85 (they are set as a ground activation). Just make sure you wire the relay correctly by testing what the green and blue wires do. Hope this helps.
Your fan needs to be wired to the blue and black wires. The Sniper's light blue fan control wire should be connected to the green thermo control wire in the harness.
Dave
brewha
06-15-2019, 08:29 PM
The green wires are the ground for the fan. There are actually 2 green wires and both should actuate the fan. Most people use one to the EfI which controls the ground of the circuit per temp and use the other green wire as an override to a toggle switch. I believe the blue wire is the power wire.
boat737
06-15-2019, 10:32 PM
The green wires are the ground for the fan. There are actually 2 green wires and both should actuate the fan. Most people use one to the EfI which controls the ground of the circuit per temp and use the other green wire as an override to a toggle switch. I believe the blue wire is the power wire.
Just to make this clear, the green wire(s) are the grounding circuit for the fan relay control. They are not the fan ground. i.e. when you supply a ground (through a thermo switch, manual toggle switch, etc) on the green wire, it activates the fan relay, and supplies power to the fan (blue wire I think). I know what you meant, just wanted to clarify.
brewha
06-16-2019, 05:19 PM
Just to make this clear, the green wire(s) are the grounding circuit for the fan relay control. They are not the fan ground. i.e. when you supply a ground (through a thermo switch, manual toggle switch, etc) on the green wire, it activates the fan relay, and supplies power to the fan (blue wire I think). I know what you meant, just wanted to clarify.
Agree with what you said....:)
Randy's
06-17-2019, 10:17 AM
Papa (Dave),
Many thanks. I wired it as you said to do and it works great. It's funny how after you get it right it all makes sense!
Papa (Dave),
Many thanks. I wired it as you said to do and it works great. It's funny how after you get it right it all makes sense!
Good to hear you got it working.
Dave
acmikee
06-17-2019, 11:16 AM
I like the derale fan controllers which controls the fan speed to keep a constant temp.
https://www.summitracing.com/parts/der-16795/overview/
Railroad
06-17-2019, 01:44 PM
I like the derale fan controllers which controls the fan speed to keep a constant temp.
https://www.summitracing.com/parts/der-16795/overview/
I was about to jump on this for another vehicle until I read the reviews and customer service.