Daisy's got a point, in that explaining why can help. But you have to rally be careful to not seem as if all you are doing, is opposing him - because that teaches a kid that being oppositional is a valid coping strategy.
I really LOATHE the term Oppositional Defiant Disorder. It implies that the child is choosing, deliberately and coldly, to do exactly what you have asked him not to do. And I do not believe this is the case except in very rare circumstances. It does not sound like it here.
it's not like i'm asking too much.
Actually, I think you are. It doesn't seem to make sense, but I really do think there are two possibilities you need to have on the table:
1) When caught by the impulse of "I want to do that NOW" he just forgets the rules even though in the cold light of day he could probably recite them verbatim. difficult child 3 at school, knew the rules included not hitting other kids and not climbing trees. But at home he would climb trees so he would forget at school, then get into trouble. As for hitting other kids - they would make him angry and he would lash out.
2) He might still have the rules in mind, but the drive in him (for all sorts of reasons) is stronger. You need to find out why and deal with that more directly, including listening to his why and working with him to find more acceptable alternatives.
With DaisyFace's suggestions, I would take it further away from discipline and more towards natural consequences. That way you are not the ogre, life is. Or circumstances. Natural consequences. For example, the hallway light - if you remove the light bulb, you could tell him it burned out from over-use. Or show him the power bill, tell him you need to make those numbers smaller.
But I do think it is is important to find out why he feels he has to do this. Right now I think he is getting into a pattern of choosing to do what he wants even in the face of your direct disapproval. Some people would define this as ODD; I think it is much more complex and needs to be dealt with by the direct approach. When he does this, follow him. Go into his room and ask him quietly, "Can you tell me why you needed to turn the hall light on? Do you need it on AS you go into your room? Now your door is shut, can I switch the light off now?"
Kids have their reasons and if those reasons are really, really strong, they will over-ride your rules. So you need to find out HIS "why"s and try to get him to take on board your own. But his have to be considered, so they can be dealt with.
For example - I'm wondering if there is something in his room that scares him a little, in the full dark. He feels the need for some light to spill into his room until he gets to turn on his own room light switch. Once his room light is on, the hall light may not be needed any more.
Kids fears are very strong, very concrete. When I was little, I shared a bedroom with three sisters. I could not reach the switch for the light but had to rely on them to turn it on. Until the light was on, the room was a scary place. At night I had nightmares and night terrors, turning on the light was a huge help for me. Of course, I was not permitted a night light. I would have loved my own low-wattage bed lamp, knowing I could turn it on if I needed it would have helped. The nightmares and night terrors eased off as I got into my teens but they continued until I was married. I am certain that if I had been given a bed lamp when little, this would have resolved many years earlier. Things did ease off a lot for me once I was able to organise my own bed lamp. So I really do understand kids who feel they need light. Something is happening in his head that makes it most imperative for him to have that hall light on at some point. Fid out why, when and how, and work WITH him in this.
Also, you mention a lot of things he does that he shouldn't. Some kids with ADHD have serious impulse control issues. They know the rules but the spur of the moment stuff - the rules just don't figure. I have to do it now. Intense curiosity can be a factor. Example - when difficult child 3 was born, his godmother came to visit with her teenage kids. Her son was 12 and ADHD. Lovely kids, but the boy was always a handful. He of course got bored (breeding women talking about babies) and after he had seen enough of the baby, he looked around. I had a balcony outside my room and he went out there. Looking down he could see below, a roof of a lower floor which had paving pebbles on it. It was actually there to allow access to the air conditioning units for the wing below. it was NOT public access and if he had stopped to think, he would have realised this. But it still might not have been enough - there were machines and things down there, he wanted a closer look. So he wandered off, wandered downstairs, walked through another patient's room downstairs to get access to the balcony, climbed over the balcony and went for a walk on the roof in the maintenance area. The patient called the nurses who called security. The first we knew of it was when the boy was brought back to us (he cooperated openly, told them who he was there to visit) and we were told to get him out of the hospital fast. My friend had to leave earlier than she wanted, because she realised he just couldn't be trusted to follow the rules. In his mind it was OK to do what he did because there was no sign saying he couldn't. He didn't have the common sense to tell him that if you have to climb over the balcony to get access, it is not for the public to go there.
All through that boy's childhood and adolescence, there were incidents like this. He really was a lovely kid, basically honest and caring. But oh, the scrapes he got into! At his 21st, instead of childhood photos marking various points of his life, his mother put up X-rays. He's turned into a decent, responsible young man who has learned from his mistakes (he made enough of them!) and is a valued employee at a major TV network. But his mother's grey hair is mostly down to him!
You need to find out what is driving your son to do what he does. And once you know, then work within that framework to get what you want. Whatever discipline method, whatever consequences - it needs to be enforceable and consistent. There is no point saying to a kid, "Don't do that again or I'll do X" if there is no way you can or will do X. We stopped sending difficult child 3 to his room, when he would not go by himself and when us taking him there became a huge physical ordeal with no lesson learned. We had to find alternatives that would work. being sent to their room worked for the other kids. But with difficult child 3 - he needed to talk at us. So if we didn't want to listen, We would go to OUR room!
I found the greatest improvement in difficult child 3, when I started reading 'The Explosive Chid" by Ross Greene. I was only reading the book; I didn't feel I was doing anything different. But I must have been. I just don't know what. But he began to improve, for me. He got worse, for husband. It took longer for husband to get on board with Explosive Child simply because I had to read it first and explain it to him. That takes time. But that delay meant that difficult child 3 perceived husband as the focus of his problems and conflict.
Some kids, most kids, learn by traditional parenting. We try to raise our kids the way we were raised. But some kids, our kids, are much more imitative than we were. These are the kids who "Do as I do" and not "Do as I say". To various extremes. When you say to such a kid, "Because I said so, that's why!" you need to be prepared for that kid doing exactly the same back to you at some stage. And to that kid - YOU said it, so it must be ok for him to say it. We found with our two younger kids, we had to change how we handled them and model for them, the behaviour we wanted from them.
That's not to say I didn't smack my kids at times. But we phased it out as soon as we could because it was the wrong way to go. Again.
ADHD can explain everything you describe. And it doesn't have to just be ADHD - some kids just can't seem to walk on the ground, they have to get around as much as possible without touching the ground. At school easy child 2/difficult child 2 used to get into trouble constantly for walking on the handrails, for walking along any narrow bit of pipework or building trim. Then the school brought in some circus performers and we discovered - easy child 2/difficult child 2 is a natural. She began working professionally as a stiltwalker when she was 10 years old. But along the way she learned how to do it safely, and organised her own insurance.
Find out what is driving him, and work from there. Because whatever you're doing now is not working. And it's not a matter of your fault or not. It just IS.
Marg