MarchHare2008 Posted April 20, 2009 Share Posted April 20, 2009 I will be wiring in my Autocom next weekend and will locate the unit on the rear bulkhead between the seats. Ideally I'd like to use a power source from the back end of the car to avoid having to run wires through the cockpit. Does anyone know of a suitable source. It needs to be powered up by the ignition as I don't want to flatten my battery by forgetting to unplug a headset. The unit instructions suggest a brake light power feed. Presumably this would have to be a permanent live with the switch on the negative side of the light circuit. Is this the case in a Caterham? Link to comment Share on other sites More sharing options...
Bellissimmo Posted April 20, 2009 Share Posted April 20, 2009 My car (2008 Roadsport) had a wire already built into the harness that came out around the diff area. It was even terminated with the 'standard' connector for a power socket (a pair of femail spade connectors in a 'T'shaped' moulded cover. Don't know when they started putting these in the loom but it's worth looking for. Steve Bonnie Babies Charity Appeal Link to comment Share on other sites More sharing options...
Paul Deslandes Posted April 20, 2009 Share Posted April 20, 2009 If you check posts from the past couple of weeks you'll see that these intercoms can suffer from alternator generated, supply-borne interference that causes an annoying whine on the headsets. To minimise the chance of this happening, you should run both +12V and -ve connections back to the battery with an in-line fuse in the +ve side close to the battery. If you're worried about flattening your battery you could include a relay that's activated by the ignition line so it goes off when the engine's off. You can run the wires under the tunnel, securely cable-tie'd out of the way. You might be ok without but it might help if you're unlucky. Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted April 20, 2009 Share Posted April 20, 2009 I took my supply from a switched live on the ignition switch and the earth to the earth point by the passengers knee behind the dash. Just pushed the wire up between the tunnel side and the tunnel top - so far it seems to have stayed put ! Link to comment Share on other sites More sharing options...
DaveMorris Posted April 20, 2009 Share Posted April 20, 2009 Agree that to minimise interference then a seperate supply/earth is best bet - though just running the supply can be good enough as long as you have a good earth point at the rear of the car. SM25T's solution does work but MAKE SURE you have an in-line fuse. The tunnel top can chafe the insulation on the wire and cause a short-circuit. If no in-line fuse then the wire gets a little bit hot and then melts 😳 Thru the tunnel is definitely best. Link to comment Share on other sites More sharing options...
myothercarsa2cv Posted April 20, 2009 Share Posted April 20, 2009 I ran wires direct from battery terminals; the intercom unit has a plug socket so when it's removed from the car, the circuit is broken - ergo no flat battery. Ran the wires down the tunnel top and out by the bulkhead, with some velcro to hold the unit. Simple. And no drilling! John _________________________ Bugsy: '82 2cv6 (Back on the road!!! 😬) Talloulah: '08 1.6K Classic (Grubby ) Link to comment Share on other sites More sharing options...
MarchHare2008 Posted April 20, 2009 Author Share Posted April 20, 2009 Thanks for the suggestions, the supplied transformer (12v to 9v) has an inline fuse fitted in the wiring so that part if it seems straight forward. I think I'll try a feed from the ignition switch, I have replaced the original key switch with an aircraft style switch on the dash so presumably one side is permanently live and the other is the switched side. Do I need to run a negative supply down the tunnel too? Can't I just use a chassis tube fitting (providing it has a bare metal surface available)? Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted April 20, 2009 Share Posted April 20, 2009 You can pick up a decent earth point in the boot. Ref the fuse in the transformer - as long as it is at the front end of the car, not in the boot ? Otherwise, for the few pence involved, fuse it where you pick up the 12V. Use a multimeter to check which terminal on your new switch is live when 'on'. Link to comment Share on other sites More sharing options...
Paul Deslandes Posted April 20, 2009 Share Posted April 20, 2009 By all means try connecting the -ve to a good chassis point but there are good electrical reasons to do with circulating currents that could still allow the noise to be generated. If the boot earth is not satisfactory, try running the -ve wire back to the battery as suggested, making sure that the Autocom doesn't make electrical contact with the chassis anywhere else and remove your boot connected wire. Incidentally, being a pedantic bstd, its a voltage regulator not a transformer which only works with ac. Paul Edited by - Paul Deslandes on 20 Apr 2009 14:07:15 Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now