[Wiring help] hold radio memory with battery disconnected?

I suspect what is going on is as follows:

1. The car’s cutoff switch isolates the ground terminal of the battery.
2. The radio chassis at the moment is also connected via its mounting hardware to the car’s chassis (i.e ground).
3. When you connect the radio ground terminal to the battery ground terminal, that wire is bypassing the cutoff switch.

If that’s true, be careful not to turn on anything else (like the starter) or you will smoke that little ground wire.

The only ways out of this that I can think of are:

1. Isolate the radio chassis from the car chassis so that the radio’s ground wire is the only thing connecting the radio to the ground side of the battery, or,
2. Don’t turn off the cutoff switch. If you are doing so to prevent battery discharge from long periods of non-use, instead solve that problem by using a battery maintainer.

 

OK, you're a witch

Seriously, don't see how that's even possible unless you have some other wiring mods -- like an alarm system that is wired to sense the doors being opened -- do you?

 

The minus side wiring network of the door lights (that gets grounded by the door switches to turn them "on" when a door is opened) is completely isolated from everything else and doesn't even connect to the fuse-relay panel (if everything is stock), so still have to conclude that there some modification somewhere in your TR. Know that that doesn't help you much.

 

Sorry I missed your comment about the antenna cable. That would do it because the other end of the cable at the antenna would be connected to ground there. So you’d have to give up radio.

 

Wow. OK. Hello all! Popping back in.
This is unsettling to say the least. I have an under-dash cutoff and after 12 years post-minor-resto including making the Kenwood work again, have not had any problems. The Kenwood has a ground and two source inputs, a very low current memory stay-alive (0.05 amp inline fuse...?) and the main feed. When I turn off the cutout, the "memory" dies but have not had any issues with smoking the ground wire. Now I am wondering how it is set up.