overdrive switch for a kill switch

OK, have to admit that this may be a wierd idea. Re-wiring the dash, trying to sort out the mess. Traced a wire back to the wiper switch and found that it was for the overdrive, which I do not have on my car. So, we were wondering if I could use the switch for something else and came up with an idea to tie it into a relay that kills the power, similiar to a battery cut-off in case of an electric fire or theft. Has anyone ever done anything like this using the switch on the column to kill the signal to the relay which would be tied to main power? Told you it was a little wierd but would it work?

put in a proper cutoff switch, don't be called a DPO by the next owner.

It has been used to cut off the fuel pump voltage supply. Fairly easy to do without cutting any of the harness. In fact, you could probably do it by just unplugging the white fuel pump lead at the point where the main harness meets the rear harness at the firewall and plugging it into the yellow from the switch, which is also right there. Pull the lever, fuel pump on, push the lever, fuel pump off.

I don't see using the O.D. switch for another purpose as being a DPO. Go for it. I'm going to us mine as an overide switch for the electric cooling fan.

the wiring isn't thick enough to be used to kill the voltage to the entire car.

I'm not in favor but because the switch is just too easy to hit by accident with an arm or leg and shut off the car when you least expect it. I'd prefer to see a cut off switch mounted in a more remote location where it's not subject to accidental actuation.

the od isn't necessarily connected anywhere. Mine isn't, neither end of it. The pigtail's just there in the loom.

I would use the OD switch as the low current switch to a relay, which would be carrying the higher current from the battery.

So you or the next owner is driving along, the relay must be energized, all the time, now the relay fails, a connection fails, or the wiring fails, all these things happen. Carry what you need to fix it on the side of the road at night, in the rain.

If you do it at least put a drawing of what you did in the trunk or glove box for the next guy, it will not be found on the Advanced Wire schematics.

My father wired my fuel pump to the od switch in my first GT. Never had any issues.

Bud,

I admire the thought process but personally, I'd just run a separate hidden switch with a relay.

One day you might like to have the o/d switch when you might install an o/drive.

Bumping the switch by accident popped into my head as well.

Thanks for all your input.

Fog lights? Seat heater? ( with relay)