Make 12v socket turn on/off with ignition

I have a 92 Ford Ranger that the cigarette lighter is always on. I sort of want to keep the built in one always on, but I’d like to add one that turns on/off with the ignition for the typical ancillary stuff (phone, backup camera, etc.) I’ve never really messed with the wiring in a car, but I’m assuming it wouldn’t be too hard.

Anyone have any suggestions for where to start?

Circuits in a vehicle are divided into switched and unswitched. The latter category is further subdivided into accessory and on.

Try to find a wiring schematic in a shop manual. You may have a spare fuse circuit, especially if your truck is not fully “loaded.”


Use a voltmeter to find a fuse that is controlled by the ignition and install one of these in place of the fuse. Then wire it to a new cigarette lighter plug and ground it to a metal part of the chassis or a ground wire.Best option would be to find a circuit that you are not using such as a sunroof that your vehicle doesn’t have. Etc.

These are currently on sale at Amazon
Nilight 12V Car Add-A-Circuit Fuse Tap Adapter Mini Atm Apm Blade Fuse Holder-10 Pack, 2 Years Warranty They have different fuse versions so if you are not sure , order the assortment pack


Thanks @Bill and @Jeff_Moore! I haven’t had much luck finding a switched fuse, but as I mentioned, not much experience with car wiring. I like the idea of that fuse from amazon as there are definitely unused sockets in the fuse box.

Looks like I may have to order an old Chilton manual to find the wiring diagram. The truck is bare bones, so this is on the list along with adding power windows and locks

I do not know whether Ford installs the same wiring harness into all vehicles or if they make different one for each of the trim levels, but the wiring for power windows and locks may already be there. If so, all you have to do is install switches, solenoids and motors (possibly a different window regulator.)

Ford is like most automakers - in that they used the same fuse & fuse/relay panels for many models - so yours will have spare or blank openings.

For example, as a possible unused fuse location - your truck did not have a rear window defroster or trailer brake controller option - those may have been used on that the fuse box on other models within the 5 to 10 year model range that that fuse box was most likely in service.

A quick glance at the owner’s manual on the fuse panel page will indicate which locations are not used, then a DVM or power probe will help you find out whcih of the spares is controlled by the ignition key.

Your 1992 ranger is easier than the later and current shit boxes of today that are can bus.

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You mean “can’t bus” :stuck_out_tongue:

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