There's not really any tests you want to attempt on a UBEC without a bus tester, but suffice to say (I think) most of the issues are crappy solder joints to the bottom terminals. Yes there is a circuit board of sorts inside the UBEC, but it's not really a computer per se.

 

appreciate your help , I did discover a corroded (green ) wire heading up under the drivers seat ,(looks like clear plastic wrapped buss maybe) But I had to break away from it to go to work .I am going to pull the drivers seat and see whats up with it .Do you know if a budd wire runs up under the drivers seat (heated pw seats) and if it tied into the BCM (I believe that's the faulty system BCM)

 

that corroded wire is a un-insulated wire that is wrapped(in a blue wrap) in a group (3) twisted buss wires that feed under the drivers seat and carry on in the harness toward the console . It routes the other way toward the back of the vehicle left side and is in the closest harness to the outer side rocker panel, (that area is wet in the well it routes through ) I assume that is where the corrosion is coming from(wicking water) .As it goes up the harness toward the rear it is dry and not corroded . That particular group (3 buss and straight un-insulated wire ) are unique as they are wrapped in the blue foil like covering .any idea what this group is for ?

 

do GM use silica crystals in their under hood wire harness? i'm finding what looks like crystals but no compromised wires in the harness . at first I thought I was corrosion but it looks more like moisture absorbing crystals

 

Not that I am aware of.

 

No idea exactly what the group of wires you are describing do, however if there's two twisted wires and a shield (ground) wire that harness is most likely your MOST Canbus network for the cabin multimedia system. It may/may not be related to your issues, but if the shield has corrosion it could potentially cause electrical balance issues in the ring. (fancy terminology which might not be technically correct but conveys the concept)

Pretty much any pair of wires twisted together will be CAN. They have very particular rates of twist per foot and the total wire length is specified in millimeters- any more or less causes standing wave ratio issues (and by definition- errors!). If you find a damaged twisted wire set, no touchy! Let the professionals who (hopefully) understand CANBUS fix it with their special diagnostic equipment.

I don't think silica gel crystals should in the wire harness as they serve no purpose being somewhere they cannot be easily exchanged. Once they get soggy they simply keep the water in place.

 

I am at a loss