Wiring in heated seats

[PeteT]

I have got some heated pannels to fit to my seats. I believe they are from the group buy from ages ago by tem.

In the instructions, it says to wire it into the cig lighter. I have no problem doing this, however... from the cig lighter i am currently running my TPMS and a Talex speed camera detector. Would adding the heated seats overload the system?

Any advice would be welcome

[iPap]

I would run a nice new feed as the piggy loom will have an massive load on it with all the bits working together.

Worth baring in mind also there was a recall on that or the stereo loom as it can short on the body work, so best not to overload it.

It's nice and easy to runs new feed in from the battery, through the grommet below it and down the passenger side.

[PeteT]

Thank you, If i wan't running all the other stuff i wouldn't be too concerned. Your probably right to run a new feed. I do like the idea of having the safety of turning off when the ignition is off.
Would i need to use a relay for this? I've not used of wired in a relay into anything before so i am unsure of which is the correct one to get.

Any pointers?

:edit
I've found this, would this work?
 m http://www.maplin.co.uk/ultra-miniature ... lay-218688 m

[aaronjb]

Only if you're planning on running an extension lead from your house to the car (that's an AC mains relay).

Pop to Halfords and pick up a standard 30A automotive relay (4 or 5 pin doesn't matter) and suitable fuse (if the seats don't say what rating, start at 5A as long as all wiring is at least 5A in size).

Run 12V from the battery to terminal 30 ('common')
Connect terminal 87 ('normally open') to the heated seats
Connect terminal 85 to the 12V feed from the cigarette lighter (this is your switched 'trigger')
Connect terminal 86 to ground (you can actually safely wire 85 & 86 up either way 'round as it's just a coil)

Current drain of the coil in the relay is minimal so no issues with the cigarette lighter and the drain of the seats themselves is powered from the battery direct. Fit a suitable fuse either in-line in the feed to terminal 30; some relays (Halfords sell these, at least mine to) actually have a socket for the fuse built into the relay to make things really easy.

Terminal numbers are mandated by ISO/DIN (I forget which) so are standardised and can be relied on - marked on the relay base.

[PeteT]

Aaron, this is perfect

 Thank you

[aaronjb]

No problem  s:) s:)

I'm guessing on the fuse rating a little, incidentally - use the wires that come with the heater pads as a guide and find the closest size you can in Halfords, comes in 5A and 17A ratings commonly.

Personally, though, I'd wire the whole lot in 17A cable and then use the lowest rating fuse you can get away with (trial & error if the pads don't come with a manual, though if the wire is 'roughly' 5A size it's probably a 3A or 5A fuse needed) - as long as the fuse is rated lower than the wire, otherwise the wire becomes the fuse, obviously .. and that's bad  s:) s:)

[roger]

I currently run heated seats (those from Tem), Talex and occasionally TomTom all from the Cigarette lighter.

No problems......................yet, touch wood.

[PeteT]

Thank you Roger, I think i would feel more comfortable running a supply from the battery using a relay. I forgot, i also have my phone and occasionally a tomtom running off the cig lighter.

Aaron, A trip to Maplin or Halfords is in order for bits. Now that you have me thinking about relays, i have a long term plan to get a Raspberry Pi (i have registered for one). I quite fancy creating an interface to control the relay from that via a touch screen. I have no idea how to do it at the moment but i fancy learning.