Adding a fan switch

Printed From: the12volt.com
Forum Name: Motorcycle Electronics
Forum Discription: Installing Stereos, Alarms, Remote Starters, Lights, Garage Door Openers and other electronics on motorcycles.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=43953
Printed Date: May 19, 2024 at 1:23 AM

Topic: Adding a fan switch

Posted By: wessh
Subject: Adding a fan switch
Date Posted: November 28, 2004 at 10:24 AM

Hi. I'm trying to add a fan switch and relay to a motorcycle. I know where to tap into the existing fan circuit and where to get power. I need help figuring out where to attach everything to the terminals of the relay . I have a 30 amp relay ( 4 terminals) and a 30 amp SPST illluminated rocker switch ( 3 terminals). Can someone tell me what goes where? Thanks

Replies:

Posted By: genehewett
Date Posted: November 28, 2004 at 7:11 PM

Take a look at this and let me know if you got any questions.You will need a SPDT relay inplace of your SPST one. For your switch this is how you would connect it if you use this diagram. The reason i would do it this way is when you cut on yournew fan switch it will send 12v back into the wireing harness and it probely wont hurt anything but i wouldnt want to pay to have a harness replaced when i could spent just a little more time and had no problem.

Your switch there should be a small diagram on the side of it.

One of the outside prongs is for the light inside it. It and the one labled supply should be grounded. One of the outside prongs should be labled "load" or "Acc." this is the one that goes to the relay. posted_image

Posted By: wessh
Date Posted: November 28, 2004 at 8:16 PM

Thanks. The diagram really helps. Where should I wire the relay into the wiring harness? 12 V supply from the keyed ignition? My on/off switch has three prongs. One labeled ground, load in the middle, and the other outside one being power. Should I ground both the power and ground?

Posted By: genehewett
Date Posted: November 29, 2004 at 12:54 AM

It dont make much differance where the relay is but contact #30 must go to the fan motor and #87a must connect to the other wire. For power i would use ignition power not acc. power. By using ignition power the only time the circuit will have power is when the key is all the way on not in acc. And for your switch connect ground to the middle and the other outside one (normally power) and connect 12v to the one labeled ground. I know that sounds funny but when the switch was made thay were only thinking it would be switching 12v but you need it to switch ground. You see the one labled load is for what you are turning on and off, since you need to switch ground and send it to the relay then you ground the middle one (normally the power terminal if you were using it to turn on something like fog lights). And last the one labled ground gets connected to 12v so when you push the switch on and it switches ground the light inside the switch will light up because it has 12v on the other side of it. I think you will do just fine. Good Luck!