Here is a copy/paste from this thread:
http://www.steelsoldiers.com/deuce/56739-brake-lights-work-under-brake-not-under-service.html
Lots of information out there about the push button light switch.
The 3
lever switch does a lot of things. I went through about 9 or 10 used ones until I found a unit that worked on every function when I was building the M715. I have had a pretty good run lately on the other trucks.
Here is the best wiring diagram I have ever seen about what pin does what on the
switch:
http://www.m715zone.com/vb/pages/man...g/lighting.pdf
You have to be a member of the Zone to see it though. If you don't want to go there. Look on the back of the
switch. Each pin has very faint and hard to see letters next to it. Here is a short and simple list of what each pin does:
A= power to the brake light
switch
B= power out to the dash lights
C= goes to terminal D on the blinker
switch, wire 22, it is the power out to the brake lights when A and K are connected.
D=power out to the B/O drive light
E= power out to B/O marker lights
F= Power into the
switch from the battery
H= power out to service tail lights
J= Goes to pin G on the turn signal
switch.
K= stop light
switch return to the 3
lever. Completes the circuit started by pin A with the stop light
switch in the middle.
L= parking light power
M= head light power out to dimmer
switch
N= Power out to B/O stop light
Here is a list of what wire is supposed to do what:
M-SERIES VEHICLES CIRCUIT NUMBERS
