Ok here is a quick and easy list of ways to find a voltage drain.

Needed mm I like digital. LONG set of jumper leads,hot clip
insulated both ends, screwdriver for tail and park lens.

1 Open drivers door pull dome bulb. Close door. If drain is gone
pull,check or throw drivers jam switch.
2 If drain still on hook up jumpers to meter go to taillights,pull one bulb
drain gone check t/s switch. If not go to other side repeat.If drain still
on go brake light switch r&r check .If not get under and look for caffed
or broken wire.
3 If not found go front park lamps and repeat.If pulling bulb stops
drain check or replace socket. If not check wires. If good dimmer switch
or h/l switch.
4 if still no joy.Disconnect alternator battery wire.Then field wires or
wire.

If not found yet you will have to get funny pages and go for it.

these tips are in order of most common and most abused. Als remove all
scotch locks and other lousy connections and repair.
I always run two grounds minimum. One is battery to solid
connection on motor other is sme size cable motor to frame. And if
there is a lot read 2 or more computers or black boxes
in the greenhouse.One more of battery size frame to firewall
Aways use the same size cable or wire as the power side for
grounding it carries the same load.

HOPE this helps it is my check list and works 85 percent of the time.
Also any component with a memory is a little drain 1 or 2
volts is all almost no amps.

Well my 2 cents cr

_________________
brass handled wrench,bfh and a BIG screw
driver. If it aint drawn blood you aint done.