12v Constant Source

[CheesyMong]

Hi Guys

I have my carpc wired to the 12v Constant on the stereo but it doesn't survive the crank of the engine as I believe the stereo harness does this to stop the audio pop.

Does anyone know a good easy place to pick up a constant 12v that is fused?

Cheers

Joel

[tangcla]

It's normal, I think you'll find all headunits will reboot when the engine is turned over.

[Ric]

You could use the +12V on pin 16 of the OBD2 connector (under the dash, just above the accelerator pedal).
See: http://en.wikipedia.org/wiki/Obd2#OBD-II
That is NOT interrupted during cranking.

[CheesyMong]

You could use the +12V on pin 16 of the OBD2 connector (under the dash, just above the accelerator pedal).
See: http://en.wikipedia.org/wiki/Obd2#OBD-II
That is NOT interrupted during cranking.

Cheers Thanks...not too hard to extend the wire to reach there.

I'm guessing that is fused...I'll check tomorrow but hopefully it is 15amp or more

Cheers

Joel

[Ric]

It's fuse#13 in the engine bay fusebox. It is a 7.5A fuse.
This is the fuse supplying the ECM also, so you wouldn't want to blow it!

Note, if you're looking in the Subaru service manuals, the OBD connector is "B40", and for some crazy reason the pin numbering is reversed.
Comparing to Standard OBD number:

Code: Select all

OBD Subaru Function
16  1      Battery voltage (white wire)
7   10     K+ data (Purple/Red wire)
5+4 12+13  ground (Black/Blue wire)

[CheesyMong]

Oohh starting to think that might not be a good source now )

[Ric]

Several of the relays just to the side of the internal fusebox are connected to the battery via 20A fuses. A few of them are sitting idle (e.g. "seat warmer" relay), but I'm not sure how easy they are to access.