2003 GMC YUKON XL Denali Can bus problems - need an expert... their was this mouse

[James Burt]

I have a 2003 GMC Yukon XL Denali with can bus problems / wiring problems which I believe starts with a mouse or two which I have now relocated to the afterlife.
Here's my list of problems
The following dash lights are on; Air Bag, ABS, Brake. The drivers seat heater lights up but doesn't heat up. Intermittently the voltage gauge drops out and falls then the battery lights comes on and at the same time the climate control blower motor cuts out.
Couldn't find any blown fuses.
I've pulled the SP205 splice comb and found the follow modules at ground level (dirty ground, not zero volts) per an O-scope with the ignition on - Electronic Brake Control (pin C), and pin A (radio and SP207). All the other modules on SP205 looked nice and are talking away.
I then pulled SP207 comb and pin A on SP 205 was still at zero (with good ground and power) to the aftermarket radio head unit. I have been running the aftermarket radio for years with no can bus problems.
Everything on SP207 is also at dirty ground with it's comb out. Mostly rear radio stuff, but with the comb out and ignition power on, the radio will not power up now.
I ran throw all the wiring diagrams for the items and couldn't find any common link or location.
I no longer have access to a good scanner so I don't know of any U codes.
Any good advice? - and no I don't want to get rid of it, I really like this thing, but running out of ideas now...

 

[Doubeleive]

I have a 2003 GMC Yukon XL Denali with can bus problems / wiring problems which I believe starts with a mouse or two which I have now relocated to the afterlife.
Here's my list of problems
The following dash lights are on; Air Bag, ABS, Brake. The drivers seat heater lights up but doesn't heat up. Intermittently the voltage gauge drops out and falls then the battery lights comes on and at the same time the climate control blower motor cuts out.
Couldn't find any blown fuses.
I've pulled the SP205 splice comb and found the follow modules at ground level (dirty ground, not zero volts) per an O-scope with the ignition on - Electronic Brake Control (pin C), and pin A (radio and SP207). All the other modules on SP205 looked nice and are talking away.
I then pulled SP207 comb and pin A on SP 205 was still at zero (with good ground and power) to the aftermarket radio head unit. I have been running the aftermarket radio for years with no can bus problems.
Everything on SP207 is also at dirty ground with it's comb out. Mostly rear radio stuff, but with the comb out and ignition power on, the radio will not power up now.
I ran throw all the wiring diagrams for the items and couldn't find any common link or location.
I no longer have access to a good scanner so I don't know of any U codes.
Any good advice? - and no I don't want to get rid of it, I really like this thing, but running out of ideas now...

I would pull everything out that you can plastic trim pieces, radio, cluster, hvac, bcm, passenger airbag, center console.
then start inspecting wires and repair as you go.