Electrical question

[rglosem]

Hello All,

Posting on behalf of my older friend/neighbor who is not very computer savvy.

Looking for information/suggestions on what is a good source switched by the ignition key for some auxiliary power.

1953 Crestline V8, converted to 12V.

PO used an original wire to the heater blower switch as a source of switched power. I am curious as to how much total power could be put on this wire? For example, if a separate fuse block was set up with this wire as the 12V source, how much total current could be attached to it. I was looking at the original wiring diagram and could not find the heater blower switch on it.

Are there any other good (and accessible) sources of 12V switched power under the dash?

 

[Kurt in NJ]

It would depend on how much is needed.
a couple amps can be taken off the ignition switch but if 30 amps is needed a relay would be needed that can be turned on with ignition switch.

 

[Drbrown]

Anything like that should be fused. A 12 volt circuit with standard wire should be fused to 20 amps. However, as "Kurt in NJ" beforehand indicates one should aqvoid overloading the key circuit itself. It should be preferable to have that new circuit from the key operate a 12 volt relay (only) mounted on the fire wall in the engine compartment. That relay could trigger a (fused) battery feed direct to your device. That gets the high amperage wiring out of the car interior and off the Key switch. Obviously all this is dependant on the condition and wiring arrangement in your particular car and more aparticular information.