Needing opinions on fixing a thermocouple thermometer-- Edit- Fixed

Scored this at work for free.

Its for measuring exhaust temps to determine catalyst efficiency(obsolete).

It appears to be unused, but as soon as I put a battery in it, it turned on and won't shut off.

I was thinking about trying to replace the on/off switch.

Now I'm thinking it may be easier just tapping into the battery circuit(wire) and adding a small external switch.

Whaddya think?

A donor switch finally appeared(aftermarket remote car starter take off).

So I spliced it into the battery circuit, and mounted it to the case internally.

Now the battery should last more then a day. :lol: