Help with fan bypass switch

[Ladders]

Hi!

I’m trying to install a fan bypass switch on my Elise.

I’ve managed to tap into the relay that controls the fan (shown on the left on the attached diagram), which works as I hoped.

The problem is that the switch that I ideally want to use, as it matches the other switches (Right on the diagram), has an Internal lamp that I want to illuminate when the fan is activated. Unfortunately this light doesn’t come on when the switch is activated, but needs a separate feed that turns it on when connected.

I thought this would be easily achieved by wiring the circuit as in the diagram, but unfortunately the lamp must draw so much current that there is not enough to trigger the coil in the fan relay.



I thought that I could use a micro relay in line with the switch, than use that to switch the light on, but that also uses to much current.

I’m wondering if I could use a solid state relay in line with the switch? Would that draw less current than a normal relay? Or is there existing circuit etc or even one that I could build that would do the job?

Any help gladly received!

[ian332isport]

I don't think that it's the lamp pulling too much current. I think the lamp is stopping the bottom of the fan relay coil from getting close enough to ground. You obviously have ground on the bottom of the lamp, but the voltage at the top of the lamp (effectively the bottom of the relay coil) will be at a higher voltage.

This would probably do the job.

[Ladders]

Hi Ian, thanks for that.

I have actually tried that, and it works, but the only thing is that when the fan spins down it carries on illuminating the light. This isn’t a big problem to be honest, but I’m thinking that when moving along the fan could spin in the airflow and illuminate the light again?

[Ladders]

Finally worked out a way to do it, used a relay to control the connection to the fan relay in the end as below