1994 Mazda

Not familiar with the vehicle in detail. One place I would look is some protruding button or such that is located around the ridge where the hatchback door seals to the car. As the door opens, the pressure on the button it taken off and the light automatically goes on.

Such a button might conceivably be on the door as well, where it closes against the car, but that is less likely.

If you can't find a switch, use some black duct tape.

I prefer orange tape myself.

If you have a screwdriver handy, you can unscrew the dome light casing and remove the bulb.

I assumed she/ he might want to have quick access to on or off. I thought a bit of tape in black (NOT that horrible orange color so popular these days) would be a quick and easy solution. Peel it off, put it back on.

Thanks Blick for your observations. Next I shall feel round the rubber seal, supposing the button to be hid underneath

By the way don't you think hiding the button was kind of dumb, 'spec'l'y an SUV

Blat thanks; however the object is not to dim the light but to turn it off for the sake of the battery charge

One thing you might try, maybe when it gets dark out west, is to unlock the hatch door while pushing forward to prevent the door from moving. Once you unlock the hatch door, see if the light goes on even if the door hasn't moved. If the dome light doesn't light then, slowly let the door open until you can see the point at which the light switches on.

If the light switches on when you turn the key and the door hasn't moved, then there is a good chance the light switch is in the locking mechanism or something. If the door has to move a little bit before the light comes on, then some sensor or switch must be activated by the door moving. How far the door must move before the lights come on might give an indication as to where it might be.

Interesting idea Blick, I shall try it