blackout switch tt and sw termials

[andy]

in the lighting diagram from tm 9-1701c there is a section with a note on  the blackout switch terminals. Im kinda lost about the tt and sw terminal and what they are saying?The way i read it is,,, if you have a 3 position switch use tt, if you have a 4 position switch use sw? with the number 14 wire

Andy

[spec4don]

Andy I had a 4 position switch but I couldn't make head nor tails out of things. So I just used a meter until I figured it out.

Don G.

[HenryVIII]

Andy,     I Think that wiring one way to (TT) the brake light will work all the time,  and the other way to (SW) the brake light will only work when the switch is in a certain position. It would seem to me that if you were sneaking around in the dark, you would not want to be flashing your brake lights. It may be the other way around though. I have a spare switch and will check tomorrow and let you know what I find. I wired mine a while ago and cannot remember anymore.

Henry

[spec4don]

On the 4 position switch. All the way out will allow your brake light to work with out anything else on. Not sure about the 3 position. The first notch will power up you black out markes and tail. That is the feed that also will jump over to power up the blackout drive swtich.

I believe it is the same switch that is used in the jeeps and other vehicles.

Don G.

[andy]

So after looking at a few wiring diagrams, any that show a 3 pos. switch show tt being used, and ones showing 4 pos. using sw, so i guess its that simple. Took me a bit and alot of comparing diagrams. What im also seeing is people really don't know how these switches are suppose to work lol, me included.

also note this diagram shows the 3 pos switch hence the solid wire line at tt, and dotted for the 4 pos

Andy

[HenryVIII]

Don is right about the switch. I checked out a 4 position switch with a meter today and found the same thing as what Don Explained.  The positions are 1-Off   2-Blackout     3-Service    4-Brake light only.  If your switch has the SW terminal it is a 4 position switch, use SW and not TT, If your switch does not have the SW terminal it is a 3 position switchand you must use The TT terminal. You will not have the brake light only function on the 3 position switch. One other thing I found is that in the off position even the brake lights will not work.

Henry

[andy]

Great guys,
I wonder if no power to brakes in off pos was an extra precaution in case something went wrong and lights went on when they didn't want them too. Wonder if it is possible to make them work when switch is off

[spec4don]

Andy, you could make it hot all the time just move it over on the hot lead coming into the switch. However if you do that just make sure you protect the circuit. The brakes lights on your car are the same way,

Don G.