Phil, post a pic where you replaced the fuse.

 

According to the '04 diagram, only two things connect to the CIG LTR FUSE (15A Underhood Fuse Block just to the right of the fuse in hummerz diagram )

1. The OBD2 Connector Pin 16 (DATALINK CONNECTOR)
2. The CIGAR LIGHTER (LHS nearest to the driver)

Either there's a faulty Cigar Outlet or something else is connected to that circuit causing the fuse to blow (Caution power outlets are "Hot" all the time)

Accessing the Cigar Outlet connector, I think, requires removing the center console (moulding between driver & passenger seats)

Does your radio turn off with the ignition?

 

Ok, so first I’ve replaced the cog lighter fuse and like I said it blows within 3-4 days, I just replaced the IPC/DIC so I guess I need at least until tomorrow to see if it blows or not! So far the CEL hasn’t come back! And no, the radio works just fine!

 

Someone has tied something into that cigar fuse circuit. There is literally nothing active on the circuit that can blow the fuse unless you are using an actual cig lighter or something in the far left socket (the other two are on a different circuit) or plugging something into the OBDII port. The wire to the port only powers something plugged into that OBDII port.

So if that fuse is blowing, then something is either tied into that wire for constant power (very often places will use that for constant power for stereos, alarms, or remote starts) or that power wire is shorted somewhere. Regardless, even with the fuse blown, that will not affect the vehicle systems in any way whatsoever, it will only make it so a code reader or Tech2 will not power up when connected to the OBDII port and the left power outlet will be dead.

 

Box appears clean, cant see the contacts for the fuse? With the P0650 gone, drive on!

 

There is some sort of aftermarket doodad there between the box and the fender....

 

So far so good but I’ll update you guys Tomorrow! Really hope that this will fix the issue! Appreciate you guys thank you so much

 

What's the bettin that "doodad" is connected to the fuse....

BTW your brake fluid is low, maybe your pads are worn....

 

My guess is the light bar that was on the roof! I’ll post some pictures of where I see the wires running through!
in regards to the brake fluid, can I just top it off with regular brake fluid? It was my mechanic that replaced the master cylinder but didn’t do a good job by what I can see!

 

Use only ACDelco DOT 3, I think the P/No is 19353126 but I'm sure someone will confirm this i.e. not just any regular brake fluid.