In article ,
"Bill" wrote:

The cigarette lighter should be about the same as the battery. This would be
measuring DC volts with the multimeter.

1. Does the ignition switch need to be on for this to work? Also be sure you
are measuring directly to the socket itself and not through any plug-in
device (which could change the voltage).

2. The problem could be with the +12 volts which would be the center of the
socket, or the ground which would be the round metal. Get a long wire or
jumper cable and connect it to the + of the battery, then measure from that
to the ground of the lighter socket (this tests the ground). Then switch the
cable to the ground on the battery and measure from that to the +12 center
connection on the socket (this tests the +12).

If the ground is bad, check the ground connection to the socket.

If the +12 is bad, check the fuse and measure for +12 at the fuse. If +12
good at fuse, but not at socket, then problem with the wire or connectors
between the two.

If the +12 is not good at the fuse (you would probably be having problems
with starting your car in this case), check all main electrical connections
and wires.


Yeah, all good ideas to troubleshoot a lighter socket that isn't
working. The OP's lighter sockets are working.