Manual overide for electric fan temp controller

Post by **Datrock** » Wed Feb 01, 2006 6:12 pm

Is there anyone out there running an electric fan that is wired up with a relay, like from the tech info on this site, and also have an manual overide toggle switch. I'm putting a 14 inch puller on a 68 stoker car and want to be able to overide the temp sensor control. Not sure if I would have to add another relay to make this happen. Any sugestions would help me out.. Thanks Bill

Import_sounds-of-mid-GA · Wed Feb 01, 2006 6:16 pm

I can ask my dad... he told me how to do it(i think) but i didnt have any extra money to get the temp sensor control..... lol, i used his wire, relay, and switch.... and got a free fan from a junk maxima.

Post by **Datrock** » Wed Feb 01, 2006 6:29 pm

Thanks Evan, If you could ask him I would appreciate it. It is probably easier than I think but with electrical parts, some times you just don't want to trial and error to figure it out.. Bill

Post by **reblues** » Wed Feb 01, 2006 8:07 pm

The temp control relay that came with my temp sensor has a seperate wire that could be connect to a switch.

Richard

Import_sounds-of-mid-GA · Wed Feb 01, 2006 9:42 pm

Bill Cole wrote:Thanks Evan, If you could ask him I would appreciate it. It is probably easier than I think but with electrical parts, some times you just don't want to trial and error to figure it out.. Bill

I hate dealing with electronics.... i have this nightmare of me wiring my radio and fan and then the wires started smokin REALLY bad(i swear i saw a flame).... oh wait.... that really happened.

WOAH!!! I so dont get this electric stuff.... but put a switch in the negative side wire so you can control the ground....pretty sure thats what he said!

Daryl Smith · Post by **Daryl Smith** » Thu Feb 02, 2006 9:17 pm

What you are asking is actually pretty easy, but I'm unsure of how to explain it.

Basically, you are just wiring in the switch PARALLEL to whatever is controlling the relay now.

<"Add wires to terminals 85 and 86 on your relay (from the diagram quoted) and take them to the switch you want to use.">

OK, have to edit this because it is actually quite WRONG!

The above would cause a serious SHORT CIRCUIT and blow the fuse at the least!!

(I'm surprised you guys didn't catch me on that!

)

Just take switched (on/off with ignition ) 12V power to your overide switch, then from the other terminal of your switch to terminal 85 on the relay (according to this diagram: www.derale.com/instructions/16738instruction.pdf )

That's all there is to it.

You should now have 2 wires connected to terminal 85.

Cheers

Post by **dbrick** » Thu Feb 02, 2006 9:50 pm

Daryl is on to it. I have my relay wired battery hot and switching ground through the temp sensor so my fan switch just grounds the same terminal at the dashboard. Nice part of ground side switching is if the wire rubs through on something, it just turns on, no smoke. I also found a way to mount a switch under the dash without making a hole and it has a light too. PM me and I'll give you my Phone # or give me yours, it's better to talk than type.

Post by **Datrock** » Thu Feb 02, 2006 11:52 pm

I ended up buying an adjustable Hayden model with a built in relay. The wire harness has a green wire for the A/C clutch and that is what I am supposed to hook up to a toggled ignition wire for an overide. I would like to do the negetive switching but I have not sure if I have figured the wiring setup out to do it that way. I hope this makes sense.
The wire harness on the contoller/relay is set up like this:

Large Red- battery in
Small Black- to ground
Yellow- ignition switched wire or positive side of coil
Orange- to fan
Blue- to #2 fan
Green- Positive in from A/C clutch
Gray/BlackThermal temp wire

Do you wire the fan positive wire to the battery thru a fuse then hook the fan ground to the red controller wire that should be connected to the battery, but is not. Then I can hook the overide ground switch wire to this connection since it is being used as a ground.

After that I ground out the black wire on the controller and connect the yellow to the positive side of the coil.

If I do this I will not be using the Orange and Blue wires that should power the fan(s) and the green A/C clutch wire.

The wiring harness comes out of a resin sealed base with a 30 relay plug on the face of it. It is a clean look with no metal brackets or spade plugs to mess with. Thank you very much for you input .. Bill

Daryl Smith · Post by **Daryl Smith** » Fri Feb 03, 2006 8:29 pm

I just went to the Hayden site. found a picture of some relays, but no wiring diagrams.

Instructions in the installation manual to wire up a manual override.

"The wire harness has a green wire for the A/C clutch and that is what I am supposed to hook up to a toggled ignition wire for an overide. "

"Toggled ignition wire"? I'm sorry I have no Idea what is being refered to.

It is kinda fuzzy, but, this green wire for the A/C clutch sounds like it would connect to the positive side of the relay, and you MAY be able to take a line from the FEED side of your Hayden harness to a switch and back to connect to the green wire......
Does that make sense?

Please post that excerpt from the manual and we should be able to figure it out.

Post by **Datrock** » Fri Feb 03, 2006 9:04 pm

I got the harness installed today and the !4 inch puller fan works great. I installed harness just like the instructions said to. Sorry no negetive switching, at least this time.

The toggled ignition I was referring to was a dash mounted toggle switch that would activate the green wire in the harness, with the power source coming from the ignition wire that has power to it when the key is in the on position.

What I ended up doing is using the service brake switch. Yes, It now gets to be used to turn on the overide function to the fan. This will only activate the relay to run the battery power to the fan. I unhooked the wire going to the dash light and hooked up the green A/C clutch wire from the temp/relay harness.

If you go to the Derale site. They have the same unit with a PDF of the instructions. They sell thru Summit Racing. The local parts store I went to opened the hayden box to let me compare to the picture I downloaded. It is the adjustable one with the built in Bosch type Bueller relay. The store also had a cheaper non-relay model that only ran 15 amps. Thanks for the help... Bill

Post by **Datrock** » Fri Feb 03, 2006 9:16 pm

Daryl, Look up the Derale instructions for 16759 model, it is the same as I bought The instructions for the 16738 model tells about doing the overide switching with the green A/C wire. Bill

Daryl Smith · Post by **Daryl Smith** » Fri Feb 03, 2006 9:38 pm

Sounds like you've got it sorted out. Great!

I just recently put a 14" electric fan which so far works great in the driveway.

forecast is for a little dry weather coming so maybe I'll be able to get it out for a quick drive!

Post by **dbrick** » Fri Feb 03, 2006 10:08 pm

I put a 16 inch pusher in my 2000. Still trying to sort out the thermostat placment. I have a good one that will mount in the thermostat housing, just have to tap it 1 size larger. Moves LOTS of air, Lots of Amps too.

Import_sounds-of-mid-GA · Fri Feb 03, 2006 10:19 pm

I can feel air being sucked in front of the car from my maxima fan...