All right so I’ve being driving the Hummer all morning and even when I turned it on for first time the light didn’t come on! Usually it would come on right away and then would go off and it would be like that all day! I also topped the brake fluid off and I can feel the difference! Thank you guys so much and happy thanksgiving to you all!

 

I've never purchased ACDelco brake fluid, neither for my vehicles nor 10's of thousands of customers vehicles, I've repaired over the years.
Don't look at the bottle, just check where the Brake Fluids are manufactured. Another thing to consider, DOT 3 vs. DOT 4 Brake Fluid: What’s the Difference?

 

One other thing. Blow the dust out of your fusebox. It is really dirty inside.

I would also remove the aftermarket black box contraption out of the vehicle, and repair any connections.
Aftermarket stuff is often installed by hacks that do not know what they are doing. And then causes trouble down the road.

Solder your connections during repair, and use heat-shrink tubing (the 3:1 that has glue inside).

As you often see on this forum, electrical gremlins are common on the H2 after people hacked up their wiring harness.

 

Ok guys so the CEL came back on but I think I tackled it down! So here’s what I did!
I connected my obd2 (after replacing the cigarette lighter fuse AGAIN) and I got P0650
I replaced the IPC fuse again
Waited 5-10 min and connected the Obd and no codes whatsoever!
been driving it for an hour and no light thus far!
I think I have a shorter somewhere but here’s the thing, I don’t know much about electrical stuff so if you guys could tell me where/what I can start checking It would be very helpful

 

what does this do? hummers do not come with this.

 

That’s for the roof light bar, I’m taking it out today! At this point I feel that I cannot trust my mechanic because he wasn’t even able to fill up the master cylinder properly so I don’t know where to go or what to do! Are any of you guys from NY?!

 

Filling up a master cylinder is a SAFETY ISSUE. Unless you have a leak, the mechanic failed to check the level.
And as such, he is incompetent and not to be trusted.
Ask your local hummer club members who they use (if you still have a club in your area, if not, then an offroad club). Or take it to a place where they work on offroad vehicles.

Failing that, or if you do not mind spending more money to do things right, take it where it is supposed to be taken in the first place, a GM dealer who used to be a Hummer dealer.

 

Phil, remove the cig lighter fuse, drive on and see if cel stays off.

 

I did that and it came back on! The error keep being p0650
do you think it can be the instrument panel cluster?

 

The cig lighter fuse cannot cause the CEL to come on. The ONLY things that connects to are the left cig lighter outlet and the power wire to the OBDII port. The only way it being messed with can cause an CEL light is if someone tied something else into the power wire somewhere for something that also has ties into something else that can trigger a CEL light. Possibly something connected to a class 2 data line like a remote start, alarm, stereo, or onstar integration component (aftermarket bluetooth), possibly a GPS tracking device or something. Its is an odd one but could also just be a coincidence but again, nothing should also cause that fuse to blow either as it should only be providing power to 2 points which in general use have nothing drawing power from them unless something is plugged into the OBDII port or the left cig lighter.