where to tap into ignition power 12v? (1 Viewer)

[FirstToy]

I want to wire up an aux 12v fan to turn on and off with the ignition. (so I don't have to mess with it). I believe it pulls about 6-7amps, possibly more at startup.

I do not want it to work with A/C, pressure or switch.

Suggestions?
Thanks

 

[jonheld]

Use a relay. Grab the logic +12 off of the IGN fuse and the load side +12 off the battery.

 

[FirstToy]

Jon,
Sorry I'm a real novice with electrical.

logic +12 ? I don't know what "logic" is.

So tap the + (POS) off the IGN fuse and + (POS) off the battery
both into a relay and + (POS) from relay to the fan

-(NEG) from fan to ground on the body

Is this even close? thanks for your patience

 

[Chaldaean]

... Grab the logic +12 off of the IGN fuse ...

Tapping into the cigarette lighter wire would also work (to feed the non-load side of the relay).

The Tap-In Squeeze connectors make it pretty simple: Wire Tap-In Squeeze Connectors (10-Pack) - RadioShack.com

 

[FirstToy]

ok I understand now. Thank you guys!

 

[jonheld]

Tapping into the cigarette lighter wire would also work (to feed the non-load side of the relay).

The Tap-In Squeeze connectors make it pretty simple: Wire Tap-In Squeeze Connectors (10-Pack) - RadioShack.com

Not if he only wants the fan to run with ignition on. Cig lighter is hot with ACC.

Relays have 2 "halves". A low amperage side that pulls in the internal contact(s) (logic side) and the load side which (depending on the rating of the relay) can handle high current draw. In this case, you're activating the relay when the IGN fuse is hot and that closes the internal contacts and allows you to power the fan directly from the battery.

Clear as mud?

 

[george_tlc]

Tapping into the cigarette lighter wire would also work (to feed the non-load side of the relay).

The Tap-In Squeeze connectors make it pretty simple: Wire Tap-In Squeeze Connectors (10-Pack) - RadioShack.com

PLEASE DON'T use those kinds of wire tap connectors - you are just asking for long term trouble especially if they are exposed to the elements. Basically junk that will let you down when you most need it to work.

Stripping back some insulation and providing a quality solder joint and then covering with liquid tape is a much better solution, even it if takes more work. I prefer to the use some self vulcanizing tape over the liquid tape covered soldered area for long term durability. Anyhow, do it once and do it right.

cheers,
george.

 

[FirstToy]

I'll look to splice into the ignition

Here is a diagram of what I'm thinking.
Also, is it ok to wire a second accessory like the diagram I put a box around?
or is it better to just wire two seperate systems

Thanks guys, I will take a bit of time to splice in and liquid tape since this will all be in the engine bay.
I appreciate it- as rudimentary as my knowledge is on electrics-
it's very helpful.

 

[jonheld]

Conceptually you are correct, but the logic side of the relay will need a seperate ground. You need to add a fuse between battery positive and relay. Also the IGN fuse is in the fusebox by the driver's left knee. Make sure you cut in on the load side of the fuse so the relay logic is fuse protected as well.

 

[FirstToy]

thanks Jon!