Max. safe current draw across stock 36 Ford ignition/ on-off switch?
 

I’m building the wiring harness for my 36 coupe, which is 12 V negative ground. Stock flathead powered, power-master alternator and starter, and electric fan via a fan relay. Headlights TBD. Also an under-dash Arvin heater with 12v fan. I’m guessing with 12v power my current draw across the stock on/off column drop switch won’t be a problem, but figured I would ask those who have been down this path before. I know I can add relays and or an additional master on/off switch for devices powered by “ignition” (aka not constant 12v) power, but it’s simpler to just put them all through the stock switch if it’s robust enough. And simpler is always better.
Thanks!
Pat

Re: Max. safe current draw across stock 36 Ford ignition/ on-off switch?
 

install a relay operated by the collum switch

Re: Max. safe current draw across stock 36 Ford ignition/ on-off switch?
 

When I made my harness I had similar concerns as you. So, I got a simple 4 fuse panel from ebay, and used a relay to trigger it from the stock switch. The diagram is here on the barn if you search. On mine, I ground the IGN switch, to trigger the relay. This is for heater fan, cig lighter socket, and radio.

Re: Max. safe current draw across stock 36 Ford ignition/ on-off switch?
 

Stock switch is not robust enough, let it power a relay, as said above.

Re: Max. safe current draw across stock 36 Ford ignition/ on-off switch?
 

It is not so much the current alone that does damage to contacts but the wattage. The watts are V x I The original switch is most likely good for about 40-45 watts peak and only carries about 30. W continuous.

Re: Max. safe current draw across stock 36 Ford ignition/ on-off switch?