Fan Wiring Question

[gkp200]

So I'm adding a manual fan switch with the fan thermostat control. I've searched for wiring and the posts I've found mention a brown "fan switch feed" wire and an orange "cooling fan" wire. It looks like the wiring has changed. I have a blue "cooling fan" wire and a green "fan thermo switch" wire. Can I assume the previous orange wire is now blue and the brown wire is now green?

Wiring is not my best area. Thanks for the help.

Gary

[boat737]

Don't know what the older version wires were, but I have the blue and green you mention. The blue is from the relay to the fan motor. The green is a wire that gets grounded either by a manifold temp sensor switch, a radiator temp sensor switch, or a simple toggle switch (or any combination of them) to ground. Touch that green wire to ground, the relay activates and passes current to the blue wire/fan motor.

So to add a manual switch, just connect a toggle switch (in parallel to the other temp sensor(s)) to that green wire and to ground.

In addition to that (because I was having an intermittent relay and/or a relay-socket problem that was driving me crazy) I added a 30 amp manual toggle switch under the dash with a dedicated 20 Amp fuse, direct from my hot bus bar to the fan motor. It by-passes all the relays (of which I have multiple) and provides a direct power source in case of a malfunction. It saved me a couple of times. It's way over-kill, but that's my middle name. Well, actually my middle name is "If it's worth doing, it's worth over doing." (I have since finally fixed the relay and socket problem, but the manual override is still there just in case.)

[OnlyAndy]

Have a sideways question to this FAN wire question. I am out of Temp Sensor locations in manifold. Have dash Gauge sensor, Sniper temp sensor installed but this only leaves the sensor mount at bottom radiator for the electric fan. ( last hole in manifold is used for heater ) I have read this mount low in radiator is not a good location. Any really good reasons NOT to use it????? Thx

[Papa]

Have a sideways question to this FAN wire question. I am out of Temp Sensor locations in manifold. Have dash Gauge sensor, Sniper temp sensor installed but this only leaves the sensor mount at bottom radiator for the electric fan. ( last hole in manifold is used for heater ) I have read this mount low in radiator is not a good location. Any really good reasons NOT to use it????? Thx

The Sniper will control your fan, no need to add another sensor. Just connect the Sniper's fan control wire to the green fan wire in either of the two RF harness locations.

Dave

[ptstew]

Don’t know what engine you have, but I drilled and tapped a hole in the top of my 5.0L thermostat housing for the fan switch.

[CFranks]

The orange and brown were in the dash harness to add a manual override switch. I have them in mine which is an earlier vintage MK4 RF harness. From other posts my understanding is the later RF harnesses removed the orange and brown, most people were shorting them together so they could just use the thermo sensor or put a switch in parallel. The green thermo wire you found is what you use as per above methods to ground the relay. Just make sure to check your dash harness one more time, if you do in fact have the brown and orange wires they need to be connected together so the the fan relay will operate correctly. Took me a decade to figure all this out!

[gkp200]

CFranks,

Thanks that makes sense why the earlier solution said to connect the brown and the orange. After looking at the wiring schematic I could not see how that would work with the new wiring. The new harness does not have a brown or orange in the dash harness (one of my other questions since the none of the fan wiring is in the dash harness).

[OnlyAndy]

SBC in 33' hot rod... I got a thermostat with two Ports in it but its angled right at the fitting for the heater hose so can't use it. AND... thx. I did read that the Sniper would operate the fan but its not wired yet and I forgot. That will solve my issues... Thx all for the input.