Club 80-90 Forums

Hi, i got a usb port to fit instead of cigarette lighter. The rear of lighter has two brown wires together one red and one blue/Grey . The new fitting only has + and - . Am I right in my thinking the two browns are the - and the blue/grey is ground and if so the ground connects to the - on the usb /
Many Thanks.

I believe they should be:

Brown: - (earth)
Red: +
Grey/blue: light (+ when the lights are on)

So ignore the grey/blue and use the brown and red.

Yep - to confirm..

Red is battery live - permanent 12 volts.

Brown is chassis ground or battery negative post.

Grey / Blue is the dash illumination.


Use
Red for USB +
Brown for USB -

It looks like your new socket has an on/off switch on the right hand side? If your lighter socket is always powered, then unless this is turned off when not in use, it will drain your battery. They have a transformer in to drop from 12V to 5V which is always in circuit even when not in use. Probably the reason why there is an on/off switch on it?

I just found a drain on my leisure battery which was some LED roof lights I had fitted. They are remote control and of course the unit always needs power to detect if you are turning them on or off. I have an isolator switch on that circuit now!!

the current drain should be minimal, millions of people have plugin usb adapters connected to cars with permenant live aux ports and don't have issues. Modern buck converters are far more efficient than old linear voltage regulators.

Thanks all for the information . So i've wired it in red to + 2 brown to - and taped of the blue and grey light one . but the 15 amp fuse keeps blowing .
Any Ideas ?
Many Thanks.

TwinTurbo wrote: ↑06 Sep 2025, 06:07 the current drain should be minimal, millions of people have plugin usb adapters connected to cars with permenant live aux ports and don't have issues. Modern buck converters are far more efficient than old linear voltage regulators.

Agreed it is small but if you don't use your van daily and park your van up for a month or two at a time like I do, and don't charge the battery, it will be noticeable (Speaking from experience!!). If the lighter socket was not live when the ignition is off then it is not an issue of course!!

Pauld wrote: ↑06 Sep 2025, 18:57 Thanks all for the information . So i've wired it in red to + 2 brown to - and taped of the blue and grey light one . but the 15 amp fuse keeps blowing .
Any Ideas ?
Many Thanks.

Sounds like you did it right , pronbaly poor wuality USB socket

Thanks again . Ill try getting one form somewhere else instead of Amazon.

The worrying thing for me on the Amazon listing is the pic shows 240V 10amp in- line fuse, also shows it being 24V compatible, the seller doesn't get many returns though, so maybe you were just unlucky

Does it blow as soon as you switch it on for the display, or when you have a device or 3 plugged into it ?