Elecrical problem 2003 6.0 Yukon

[rod7515]

My 2003 has an issue with some type of short. The brake light in the dash cluster is staying on (very dimmly) all the time which includes with key off and all doors closed. It just started doing this 3 days ago. I also am losing my gear selection and mileage reading in the cluster along with my radio and heater control readout. Now the radio will still play but no digital readout at all. The heater will not function at all.
However 10 minutes later every thing will come back on but the parking light will still be on very dim.
I have swapped out a known good cluster with no change.
Was wondering if anyone else has had this issue and where do I start checking. I did not find an instrument panel fuse. I also did pull the emergency switch wire off but still no change.
Thanks Rod

 

[Big Mama]

Welcome to the forum from Virginia. Start with the basics of your battery, its cables, and your grounds. Does this happen more during different weather or times of day?

 

[rod7515]

Weather has no effect on this at all. It can be drizzling or dry. The other day the instrument cluster was off for 6 miles then just driving and on smooth road they came back on. The parking light I just notice on Wednesday night, so since I'm away this weekend I pulled the negative battery cable off so battery doesn't go dead.

 

[Big Mama]

Since weather is eliminated go after those ground cables. Even if they look ok clean the chassis and body where they connect and peel a little sheathing back on the cable itself.

 

[rod7515]

So last weekend while I was away I disconnected the battery so not to drain it dead. Came home Monday morning and hooked cable back up so I could use it to tow my mowers and there were no lights on in dash cluster. I ran it 3 days this week and no d cluster readout or dimly lit lights in dash. Guess I'll have to wait and see if that issue ever comes back. Must of had a relay stick or something like that.
Rod

 

[Big Mama]

It’s sounding more and more like a power supply problem but I may be wrong. Did you get your alternator and battery tested? Let me call in a couple of folks more versed than me on electrical issues. @iamdub @swathdiver

 

[swathdiver]

These problems ought to have triggered internal BCM codes that can be pulled with an IPhone or bi-directional scan tool. It does seem like a cluster issue but I would make sure the battery's state of charge is above 64% after resting for 24 hours.

There's a guy with a youtube channel, Jeffscort if memory serves that rebuilds clusters. There's a guy people on here use to customize them as well but I do not remember the details.

 

[Fless]

I did not find an instrument panel fuse.

In the underhood fusebox: