No switched 12v supply help
No switched 12v supply help
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Discussion

Andyjc86

Original Poster:

1,149 posts

179 months

Friday 28th November 2014
quotequote all
I've just finished wiring a hands free kit into a car that has no switched 12v supply (uses 5v canbus).

What I need is a switch or relay that turns on at about 13v and off below that. Is their anything out there?

Thanks

shoehorn

686 posts

173 months

Friday 28th November 2014
quotequote all
Knowing what car it was would help and there will certainly be a switched 12v feed on the car somewhere.

Andyjc86

Original Poster:

1,149 posts

179 months

Friday 28th November 2014
quotequote all
2005 passat, and before you say it, the cig lighter is constant 12v

Mr Happy

5,897 posts

250 months

Friday 28th November 2014
quotequote all
Any of the mini-blade fuses on the LHS of the dash should be switched 12v. Use a piggy back fuse to tap it like this: http://www.ebay.co.uk/itm/Add-A-Circuit-Standard-M...

Check with a meter to confirm first, obvs.

ging84

9,548 posts

176 months

Friday 28th November 2014
quotequote all
i can guarantee you there is at least 1 12v on ignition wire coming out of your fuse box which you can tap into

Andyjc86

Original Poster:

1,149 posts

179 months

Friday 28th November 2014
quotequote all
Mr Happy said:
Any of the mini-blade fuses on the LHS of the dash should be switched 12v. Use a piggy back fuse to tap it like this: http://www.ebay.co.uk/itm/Add-A-Circuit-Standard-M...

Check with a meter to confirm first, obvs.
Sweet, I've never seen them before thanks.

I've found the switched lives in the box, I just didn't fancy removing it and chopping into the wiring. Thanks

TooMany2cvs

29,008 posts

156 months

Friday 28th November 2014
quotequote all
Andyjc86 said:
and before you say it, the cig lighter is constant 12v
So use the 5v switched to trigger a relay and switch 12v from the ciggy lighter.

Mr Happy

5,897 posts

250 months

Friday 28th November 2014
quotequote all
TooMany2cvs said:
Andyjc86 said:
and before you say it, the cig lighter is constant 12v
So use the 5v switched to trigger a relay and switch 12v from the ciggy lighter.
The can wiring isn't really suitable for this as it's a data bus, it's not a '5v switched live' so to speak.

The piggy back is the easiest way, followed by spading a blank in the fusebox (ghetto), followed by splicing into a wire behind the dash (with the associated potential for problems).

PhilTD5

51 posts

174 months

Friday 28th November 2014
quotequote all
The traction control switch (if it has one) has an ignition switched 12v feed. Ive seen hands free kits wired to that on VW caddy vans