backup cooling fan switch revisited

[autox19]

I know this has been discussed so I know I am not the only paranoid person. What I am attempting to do it have a emergency/bypass switch in the cockpit to turn on the cooling fan. I could go three, Fiats in the radiator, honda's in the engine block, and my manual. but I am currently staying with the hondas as well as the manual. unless convinced otherwise (which is why I love this forum)

the switch i bought is a latched push button that lights when on. Which is good as a reminder, not that he fans are that quiet. here is the wiring drawing I got off of youtube

Where I want to inject the honda switch is upstream of the relay

I have looked and cant see where if the engine switch was on it would back stream the power. If the engine switch is on and the manual switch was on I believe the LED (pin 3) wouldnt back stream into the ground of the switch because it is an LED.

ok educate me. tell me where I am wrong or a better way.
oh, pin 4 supplies power for the switch and LED, the + is power out when switched. pin 3 supplies power for the LED and - is for the ground for the LED. pin 1 and 2 are for if you want the light lit at all times (or dim while off and bright while on)

Odie

 

[kmead]

It should work as you have it.

If the switch isn’t “on” then there is no load path through the LED to have a ground so the LED won’t light as the LED gains either its ground or supply from the change in the position of the switch.

 

[Dr.Jeff]

I could go three, Fiats in the radiator, honda's in the engine block, and my manual. but I am currently staying with the hondas as well as the manual.

I'm not familiar with how Honda does things, but is the temp switch on the engine for the fan(s) or for the FI and/or dash temp display? Most engines don't have a fan switch on them, leaving that function to the rad switch.

 

[autox19]

Good question. The b series has a switch on the block for the fan relay as well as 2 sensors on the head. One for display one for ECU. No switch on the radiator. Weird I know. Then to add more confusion there is another way the fan can get triggered. From the ECU directly. I could use this as well but then I would have to feed the led on the switch differently as the ECU uses grounding to trigger the relay. (Stock uses ground off of the switch on the block as well but I am using positive so I can light the led.)

Odie