Possessed brake lights

[Poptom]

Hi there. First post!
I have a 2007 Toyota Yaris. If the ignition is turned 'off', the brake lights work normally. However, if the ignition is turned 'on', the brake lights are on constantly (albeit a dimmer version of their normal self). Pressing the brake then brightens the brake lights. The same applies to when the engine is running. Once the engine/ignition is turned 'off', it takes the brake lights approximately 6 seconds to turn off completely.
I have changed what I think is a relay unit which I believe controls a multitude of things including fuel injection system, horn and brake lights. The relay in question is a long (column like) relay with three fuses plugged into the top of it, located in the fuse box under the bonnet/hood. Changing the relay hasn't changed anything :(
Any help would be greatly appreciated.
Thanks

[DiCaprio]

Do you have aftermarket lights, or are they OEM ?

What you described sounds like a faulty or maybe pinched relay, but you said that this wasn't the problem, so that is kind of weird.

Can you check if the brake lights also take like 6 second to go back to normal, after you pressed the brake. Or if they go back to normal instantly after you let the pedal go.

[Poptom]

Once the brake pedal is released, the brake lights go off immediately. The 6 seconds delay is only after I turn the key off.
All parts are OEM. I'm stumped.

[DiCaprio]

I had an idea, but it seems like it's something different, since the delay is only when you turn the key off.

[Poptom]

Ok. thanks for trying anyway!
Much appreciated.

[dogsridewith]

This is unusual and puzzling. Do the brake lights fade off during the 6 second interval? Or stay at one brightness and then switch off to dark all at once? The 6 seconds may indicate something acting as a capacitor (fade) or timer (steady level), neither of which the stock base car would be expected to have (or any car on the brake circuit?)
Car forums do have a fair amount of wacky light problems, where one circuit does something to another...based on observing bulbs lighting up and/or dimming. The most common advice is to check grounds. Never hurts to check/clean bulb-socket contacts. Things generally corrode worse at the back of a car due to spray off the front wheels.
Please do tell us what you find this problem to be, or what solves it.

[DiCaprio]

I was thinking about a capacitor as well.
But it's weird since all of his parts are OEM.

[Poptom]

Thanks for all the input lads.
It appears the problem lied in the connection points in the main fuse box under the bonnet/hood. I cleaned as many of the pins as I could and squeezed in/tightened the individual connections. I can't identify the exact location of the poor connection/contact but it was definitely in the main fuse box. Problem solved!