Yeah i recently did my Hilux again using above method, after a battery change or dealer service put the annoying binging back again.
Think you start with ignition off, holding down I do turn the key to ign on (not starting engine) then as above.
I also disabled the dinging then door open and engine on. Had to disconnect a wire from ignition barrel for that. Google it, I forget which wire etc
No idea about 150tho
Turning off the Seat belt beeper (1)turn the car on , do not start engine(leave you foot off the brake).cycle your trip reset knob until you it reads odo. turn the ignition back off. wait a couple of seconds (2) make sure seat belt is not fastened (3)turn the ignition back on ,do not start...
All sorted Andy. Just needed longer than 10 seconds. Mind you I did get another display up when I tried a different sequence. No idea what it was. I got a 9 came up. As I cycled it went up to about 24 then back round 1,2,3 etc so I set it back on 9. Could have been turbo boost, window winder speed, horn volume, not a clue.
I posted a question about it a while back and some people suggested it might be my radio doing some weird bleeping, for some reason best known to itself.
Whenever I turn off the ignition, my truck goes 'Beep! Beep! Beep!...' and I wondered whether it was a kind of timer to warn me to get out before the alarm was activated [a bit like the countdown beeps you get when you set the burglar alarm in a house to give you time to get outside]
But seatbelt warning makes sense, given that I'd be removing my seatbelt after switching off the engine. I'd never have made that connection though. I shall have to investigate this further. Mine's a 90 Series though. Does that have the same seatbelt alarm?
Now, if someone could tell me why the truck also sometimes starts beeping while I'm lying underneath it wrestling with rusty bolts, I could solve two mysteries for the price of one!
Has your 90 got a factory sunroof ? My 78 has one, and bleeps/chimes to let me know its open, when I open the door to get out. It also bleeps/chimes to remind of keys in ignition with door open to get out. Different series of course, and may be totally irrelevant.
Stuzbot is your Colorado an import by any chance? I ask because my brother-in -law had an import and his beeped every time the ignition was turned off and the keys where left in. It even beeped when he first got in and put the key into the ignition before he started it up.
Just looked at your post with the pictures and yours is almost deffo a uk spec model same colour as mine as well. Just thinking out loud.
If your radio is a SONY unit that will beep when the IGN is turned off to remind you to take the faceplate off before you leave the truck. Their idea of an anti theft thing, then they went and sold spare faceplates for them so..........