MGF

To the electricians on the forum - Where's the best place to tap into a 12v source that comes on with the accessory push of the start button? I'm using a the low amp + for an Airlift compressor relay (high amp 12v line will go to battery). Engine compartment fuse box? Passenger well fuse box? Which is a good fuse to use a tap on?

s2kdrifter

I'm trying to do the same thing. What did you end up doing?

MGF

I ended up running the 12v line along the passenger side frame rail and through the same floor grommet near the passenger side steps motor wiring harness. Just pull the passenger carpet back to access. Used a micro fuse tap on fuse 36 in the passenger footwell with a 15A fuse, works great.

T_R

I tapped a fuse by the passengers feet for my snowplow controller. Be sure to use a proper fuse tap and tap the power side of the fuse so your new load doesn't feed through the existing fuse. 36 sounds familiar but I forget which one I used.

TerryH22

I tapped into pass fusebox #23 for subwoofer remote turn on.

s2kdrifter

Thanks all, yes MGF, I used that grommet. I added a relay so I'm only pulling milliAmps. As such I actually want to run it in series so that I don't pass the initial design of that factory circuit. I'm going to try and run that tap upside down on purpose.

If it doesn't fit, I'll run a 1A fuse inline to limit total possible current draw and run the circuit tap in parallel.

Realistically, this is overkill. But being an electrical engineer, I just "need" to do it that way

MGF

Coming from one electrical engineer to another, I was going to set up my relay the same way, but interestingly enough, the instructions and wiring harness from Airlift only had one main 12V red wire for power that supplies the main power and relay power. After finding the hot side of the fuse rail in the fuse box, the orientation of the tap on fuse 36 just cleared the edge of the indentation for the fuse. I also measured the draw of the pump and it only pulls about 7A when running yet it fused for 15A.

s2kdrifter

Yea, the way airlift did it was interesting. I would have done it differently. At first I wanted to use only one relay and modify their wiring to split the power going to the pump and the controller then run the pump on through the relay and tie the controller to the ign tap.

But then I decided it was easier to add a relay and leave the airlift harness alone. Initially I was thinking to add my relay under the hood and use the under hood fuse box. But then that box is precisely sealed... So I decided to tap the inside one.

I'll post some pics after I finish. Will have to be after the Hawks game. ,)

MGF

S2kdrifter - separate question - have you found a switched 12v source/fuse in the engine bay fuse box? They all seem to be constantly on. Did not do an exhaustive search, but pulled about 6 fuses that I thought would be switched and they were on with ignition off. Maybe it has to do with the 30 minute power time out?

s2kdrifter

MGF, no once I realized the outside fuse box was fairly sealed, I didn't probe any of the wires for ign. Good luck!