TR2/3/3A Brake light wiring?

[Crankshaft]

For convenience in adjusting a new mechanical brake light switch, I moved the feed from A4 to A2 on the fuse block. This allowed me to adjust w/o the ignition on. Is there a reason I would not want to leave it this way?

 

[TR3driver]

The only reason that I know of: If the switch fails "on" (possibly the adjustment moves or the pedal doesn't return fully), then the brake lights can drain the battery while you're away from the car. I had that happen on an American car once (tho fortunately one of the neighbors noticed so I didn't have to deal with a dead battery in the morning).

But I like having the brake lights work with the key off, so that is the way my TR3's mechanical switch is wired. I also put them on their own fuse, better suited to the size of the wiring (and blowing the horn fuse won't disable the brake lights).

 

[Crankshaft]

Thanks for the input. Would an inline fuse added to the feed wire work ok?

 

[6TTR3A]

Thanks for the input. Would an inline fuse added to the feed wire work ok?

A2 instead of A4 & an inline fuse works for me.

 

[Crankshaft]

One last question, for an inline fuse to be effective, wouldn't I move the stoplight switch lead to A1 or A3? Otherwise the power is still coming through the horn fuse

 

[TR3driver]

What I would (did) do is take power from A1 on the control box, instead of A1 on the fuse block. That way, the current taken by the brake lights will properly register as discharge on the ammeter (if the battery supplies the current to run them). Or not show up as charge if the generator supplies the current.

But other than that, you could use A1 on the fuse block. Using A3 will leave them controlled by the ignition switch, which is also fine if that is what you want.

 

[Crankshaft]

Many thanks. A1, control box it will be. I like having the brake lights available w/o the ignition on.
Thanks again.