Seems simple (Small maybe dumb question)

So I hear most here use the tripometer to estimate gas level (say 200 miles I fill up)
Well my gauge doesn't work either. (Looked into it. Its actually missing everything between the tank and gauge)

Here's the question.
Where the heck is the reset for the tripometer?

Forgot to add 1975 MGB
Manu date says 4/75... (thought it would be a 76 but title says 75)

Under dash, right side near heater control.

behind the fresh air vent control lever - under dash

It's on a short flexible cable going from the back of the speedometer to the location already indicated by others. Sometimes, it is missing because a PO was too lazy to reinstall it, or purchase a new one.

warmly,
dave (who is working on becoming his own PO>:D<)