Ignition switch "accessory" position query

[starbiscuit]

Hi all,

Hopefully someone can help with another daft question from yours truly.

I wired my cigarette socket on the dash to the "accessory" position contact on the ignition barrel (via a 20A fuse)

I'm using "quotes" because maybe that isn't what it is.

Certainly, with key in and turned to first position, the cigarette socket goes live, which is what I wanted.
But at second position (ignition live), it goes off again.

I only discovered this after a 30 mile drive and sat-nav nagging to be plugged in. I thought it was odd, so I pulled over and stopped the bus, key back to "accessory" and the sat-nav came on again.

Is that how it's meant to work? Is it for some other feature like "you left your keys in the ignition" warning, or what?
It's a 1970 RHD, and all keys match, but the switch could have been changed.

If the switch is buggered I'd rather replace it, but if this is how it's meant to be, I could work around it, e.g. by having an ignition-activated relay to feed the "accessory" contact, so that the "accessory" contact can't back-feed the ignition circuit.

Thanks for reading

 

[Bobster]

I'm not sure what you're trying to achieve to be honest. I would either wire it to an always live like the lights or similar or to one that is only live when the ignition is switched on if that makes sense ?

 

[sparkywig]

There is no "accessory position".

 

[starbiscuit]

There are four wired contacts on the back of my switch:
- battery (red)
- ignition run (black)
- start (crank) (red/black)
- the other one (grey)

"the other one" is battery live until the key is turned to run or crank.

It's definitely not "accessory" (there apparently isn't one in the bus) by which I could power up the radio (etc.) only with keys in, and not have to power up the coil and the electric choke and all that other battery-flattening stuff on the "ignition switched" circuits.

I suspect it's meant to power parking lights or something else that I don't have
It's not on the Bentley 1970 wiring diagram.

I didn't really want to use permanent live because that would be another constant battery drain.

Maybe I will just add another on/off switch in the dash

Thanks for the answers

 

[Mr Bean]

The grey is to a warning buzzer for key left in ign

 

[subheatadey]

You have live and switch live, so when you ignition is switched on it sends various switch live to lights etc. So I would take a switch live with a low amp fuse direct from the fusebox. You can test the switch lives with a multimeter or similar. Or if you don't want to grovel around behind the fusebox you can take the instrument panel out but can be a pain with the heater levers connected or pull the radio and use the switch live from that?