Manual fan switch

[awd-turbo]

So I read a bunch of posts about setting up the manual fan switch. My car is from 2015, but it has the more recent wiring harness, I know that there was a change made. I found a post that talks about running another wire from the thermostat dk green wire, to a switch on the dash with a ground. So I did this, I wired another wire into the connection at the thermostat sensor. Turned the car to battery, the fan ran for a second, with out me touching anything. Then the fuse popped. Did I wire it wrong?

[weendoggy]

So I read a bunch of posts about setting up the manual fan switch. My car is from 2015, but it has the more recent wiring harness, I know that there was a change made. I found a post that talks about running another wire from the thermostat dk green wire, to a switch on the dash with a ground. So I did this, I wired another wire into the connection at the thermostat sensor. Turned the car to battery, the fan ran for a second, with out me touching anything. Then the fuse popped. Did I wire it wrong?

Not sure exactly what you're doing, but you shouldn't make the switch handle the current draw. Best way is to run the toggle to ground on one side, and the other terminal would go to your ground terminal on the relay that controls the fan, IF, the fan relay is being controlled by the fan sensor. In this manner, when you flip the toggle, it would complete the ground circuit and run the fan.

If your fan is being controlled by an ignition or other positive feed (NOT the constant Battery Lead), you would need to run the toggle switch in-line with the ignition source from the relay to switch. The toggle would NOT be grounded.

[JRL16]

Agreed about the switch not carrying the load. My fan turns on by a thermo switch on the motor or I can use a toggle on the dash either way the indicator light comes on when the fan does. The toggle just like the thermo switch are only carrying the ground.

[awd-turbo]

So I have been reading about a manual fan switch... And I wwould like to set one up as a fail safe because of the location of the car. Below is how I read and interpreted the wiring. But when I give power to the car it blows the fuse. Is there a better diagram out there for me to look at. Sorry, I am not good with electrical.

http://i981.photobucket.com/albums/ae297/briangray582/garage/fan.jpg (http://s981.photobucket.com/user/briangray582/media/garage/fan.jpg.html)

[srobinsonx2]

I am not an electrical expert but did find a solution that has worked so far. For full disclosure, I have only put 200 miles an the car and this is my first build. Others with more experience have or will chime in.

See post #36 in my build thread.

http://thefactoryfiveforum.com/showthread.php?22191-srobinsonx2-Build-Thread

[edwardb]

This is a bit of a confusing subject because there are at least two versions of the RF harness. Each switch slightly differently. Here's my explanation from another thread on the other forum:

Previous version: Has orange and brown fan wires in the dash harness. Dk green fan thermo switch wire in the sending unit harness. Dk blue cooling fan power wire in the front harness. No green fan thermo switch wire in the sending unit harness. Theory of operation: Fan relay is switched with +12V applied to the orange dash wire by the brown dash wire (which is connected to the +12V gauge feed) and grounded by the green wire in the sending unit harness. Fan operation can either be with a switch in the dash and grounding the sending unit wire (switch only) or attaching the two dash wires together and using a single terminal grounding sensor at the engine. If both are desired, then the Kleiner wiring is necessary using the switch in the dash and running wires from a 2-wire engine sensor back to the dash switch so that either will energize the relay and trigger the fan.

New version: Has no wires in the dash harness. Dk green fan thermo switch wire in the sending unit harness and the front harness. Dk blue cooling fan power wire in the front harness. Theory of operation: The fan relay is already powered for both the coil and the fan power in the RF panel. This is the major (and big) difference. The two Dk green thermo switch wires are both (either one) grounds for the relay. Touch one or both to ground and the fan operates. An engine sensor can provide the ground. Or a new wire to the dash with a manual switch to ground. Or both.

This is what the back of the relay looks like on the "new" RF panel I described. Sorry it's a little blurry. Best I could do sticking my phone behind the dash.

http://i867.photobucket.com/albums/ab234/edwardb123/Factory%20Five%2020th%20Anniversary%20Mark%204%20R oadster/Electrical/IMG_1451_zpsvl9jzmkw.jpg (http://s867.photobucket.com/user/edwardb123/media/Factory%20Five%2020th%20Anniversary%20Mark%204%20R oadster/Electrical/IMG_1451_zpsvl9jzmkw.jpg.html)

30 and 85 = Red +12V input. Loop is slightly hidden in pic
87 = Blue to fan
86 = Green ground wires

My first piece of advice is to confirm which wiring version you have. If you're trying to ground one of the wires in the dash and you have the "old" version, then yes you would pop fuses. BTW, your post with the schematic (or whatever it is) isn't working. Photobucket again. :mad:

[awd-turbo]

Thanks Edward...

So for the ones not electrically inclined.... You have two dark green wires. One runs to the front harness with the fan hookup and one runs to the engine harness, either one is for the temp sensor. I used the temp sensor in my manifold so that means I used the engine harness dark green wire. I pulled the front dark green harness wire back to the cockpit. I ran that dark green wire to a switch, and then I used a ground plug from the harness... That's it. In lame man terms...

[edwardb]

Thanks Edward...

So for the ones not electrically inclined.... You have two dark green wires. One runs to the front harness with the fan hookup and one runs to the engine harness, either one is for the temp sensor. I used the temp sensor in my manifold so that means I used the engine harness dark green wire. I pulled the front dark green harness wire back to the cockpit. I ran that dark green wire to a switch, and then I used a ground plug from the harness... That's it. In lame man terms...

Sounds straighforward enough and that you have the later version harness. Tell me about your engine temp sensor. One wire or two? How is it wired? Either green wire should start the fan by touching the bare end to ground.

[awd-turbo]

Engine temp sensor is one wire.... The one from ff

[brewha]

The timing of this thread is perfect as I'm installing my cooling system this week and have been thinking of wiring an override switch. This will be extremely helpful.

[edwardb]

Engine temp sensor is one wire.... The one from ff

So that's grounding through the block when it closes at the rated temp and the fan runs. The other green wire when connected to ground should do the same thing, since they're off the same terminal on the fan relay. If it's not working that way, I really don't know what to say.

My only thought is that you really don't have that version of the harness. There's another thread on the other forum and it seems pretty certain it's on older version of the harness delivered after my last kit that came with the newer one. A definitive check would be to look at the fan relay connection on the back of your RF panel. It should look exactly like the picture I posted. If it doesn't, then you don't have the newest version. Specifically you're looking for two green wires, and the two red wires with a loop between 30 and 85.

[awd-turbo]

Edward, the way I listed above works great. I wired it up last night and it is running awesome.... I just put it in lame men's terms for the next guy.... Thanks for your help.... And I have the new version of the wire harness.

[scottiec]

Okay I need some clarification. It just so happens this thread pops up while I am trying to figure this out. I have the new harness. Dan at FF told me to have a manual override switch, I need to run a second wire from the thermo switch to my on/off switch on the dash. Then ground my switch.

So my question is, can I use the other dark green wire that runs to the front of the car and bring that to the switch? That is probably there for the 33 hot rod since I think they run a thermo switch in the rad.

If either works, it may be easier for me to just run a new wire since it is a short distance

Scottie

[edwardb]

Edward, the way I listed above works great. I wired it up last night and it is running awesome.... I just put it in lame men's terms for the next guy.... Thanks for your help.... And I have the new version of the wire harness.

Great! Thought you were still popping fuses.


Okay I need some clarification. It just so happens this thread pops up while I am trying to figure this out. I have the new harness. Dan at FF told me to have a manual override switch, I need to run a second wire from the thermo switch to my on/off switch on the dash. Then ground my switch.

So my question is, can I use the other dark green wire that runs to the front of the car and bring that to the switch? That is probably there for the 33 hot rod since I think they run a thermo switch in the rad.

If either works, it may be easier for me to just run a new wire since it is a short distance

Scottie

The two green wires in the harness -- one in the front harness the other in the gauge harness -- connect to the same terminal on the fan relay. Either (or both) can be used. You could pull another wire from the engine sensor. But it would be just as easy IMO to use one of the two wires in the harness. Same difference.

[scottiec]

Edward thanks so much for the clarification!!

[awd-turbo]

Scottiec.... Pull the front wire back to the switch... thats what I did... and ground it out.... worked great!

[scottiec]

Scottiec.... Pull the front wire back to the switch... thats what I did... and ground it out.... worked great!

Will do. This makes life easy! My first start should be next weekend. IM FREAKIN PUMPED.

[awd-turbo]

Awesome man..... it is a good time.... And yes this makes it real easy...

[Just puttering]

This may be a repeat but you can connect to the green wire anywhere and it will work
If you still have easy access to behind the relay and its easier than removing the wire from the thermostat, go ahead and use that point with a new wire to your switch.

[scottiec]

Does anyone find that with the revised harness the dark green thermo switch wire to the manifold is a bit short?

[KDubU]

Does anyone find that with the revised harness the dark green thermo switch wire to the manifold is a bit short?

Yes. I extended it with a butt join.

[scottiec]

Yes. I extended it with a butt join.

Thanks for letting me know. Just making sure I'm not missing anything obvious