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Installing lighted rocker switch

2K views 6 replies 3 participants last post by  bentwings 
#1 ·
First I already did a search but didn't find what I needed.

My electric fan is on a rely circuit and has a temp sender. It's never worked right. It originally would come on at about 185 deg but then it never shut off until the motor was stone cold. Eventually the sender simply failed so I just connected the two wires and let run when ever the motor is running.

It's a two wire sender and I haven't been able to find another. I really don't even want another as it failed open and I fortunately saw the temp climbing and stopped to see what was wrong.

The fan now runs when ever the key is on. It takes a solid 20 amps so it's a big drain when the motor is not running.

I have a on off lighted rocker switch. It has three terminals. I Have the same switch on my electric fuel pump also through a relay. It works fine but I never did get the light to work.

So, how do I wire these switches so the light work?
 
#2 ·
It would depend on the switch and how it was made......

Sometimes they have a ground terminal, for the light, a hot in, and a hot out.

You would be better off using a relay with a switched 12v supplying the power to a switch then the relay coil (of course a thermal switch is the best solution). So even if you forget to switch it off, when you turn OFF the ign the pwr to the relay is also cut
 

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#3 ·
A (3) wire lighted rocker switch will have a ground wire, a feed wire and a switched wire. The switched wire is internally connected to the pilot light.

The ground is required for the pilot light.

The feed is connected to a ignition fused source.

The switched wire is connected to the load. In this case the relay coil term 85. Relay coil term 86 is grounded.

The above is for positive switching. It can be wired for negative switching as well. It depends on how the relay is wired.


vicrod
 
#4 ·
If Vic is referring to the diagram I posted....... It's actually being switched by the NEG side of the relay coil (relay terminal 85) and the POS input to the relay coil is being switched by the ignition switch(relay terminal 86) ...... so both sides of the coil are being switched. The relay terminals 85 and 86 are interchangeable, except for those relays with a diode installed, 85 and 86 are simply each side of the relay's coil and the don't care which one gets neg or pos .....

I like wiring fans in this method.......
If the ignition switch is off the fan circuit is off and vice versa.....
The thermal switch controls the neg side of the fan relay coil and I like a bypass switch just in case the thermal fails etc..... Many thermal switches switch to a engine block ground etc.....

I personally installed a Dakota Digital dual fan controller on my ride, fully adjustable On/Off temps...... pricey tho'
 
#5 ·
Thanks for the help.

Well, I went down to the car and got the switch with the idea of posting a picture.

My dog got it when I went to pick up the phone and broke it.

Here is a picture. It looks like I need to tie the center terminal to the top one and run this to one of the two wires that were on the thermo sender, and hook the other terminal to the other wire.

My wire diagram just says "to electric fan. " So this must come from the fuse block as a pos hot to the relay. The other wire must be a ground.


In other words hook the "12 volts" bottom terminal to the wire from the fuse block and hook the center and top terminal to ground wire.

I'm just going to have to test the two wires and see exactly what they are. The joy of having the wire harness concealed.
 

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