I've been chasing a electrical gremlin in a 2011 Suburban and am looking for some ideas. This truck is fully optioned and is in otherwise perfect condition and has low mileage. The problem is the vehicle will suddenly just shut down. Everything will quit. Engine and all electrics cut out (Kinda scary on the highway at 70mph!). Then from time to time the remote key fob won't activate the locks. Some times while driving down the road the locks will lock and unlock several times, the radio will turn on and off and the gauges will go in fits with needles bouncing back and forth. Now I don't consider myself an electronics expert but I've been fixing GM cars for nearly 40 years and this one has me stumped. Before you blame the battery or battery connections, I've checked and cleaned EVERYTHING! Sometimes you get in to start it and nothing? Wait a few minutes without doing anything and bingo, it starts? There are NO CODES. I think it may be a power or ground issue to the PCM or BCM but haven't had time to really get into testing everything. I'm going to spend a few hours with the scanner next week to see if I can duplicate the problem and start checking harnesses. Three GM dealers have all tried but failed to even zero in on this issue. Looking for some ideas that I haven't thought of.

Suggestions (useful ones please) are very welcome.
Jim

 

As first described sounds like an alternator, but you say the fob don't work. Maybe its going bad. When mine went out the damn thing just died on me on the freeway. Same thing u described is how it was acting.

 

Check the grounds on the back of the motor had a friend had some weird **** goin on and that was the problem

 

Ignition switch..Gm has a history of bad switches in various other rides

 

Thank you all for your replies. I'll add your suggestions to my list. If I find the problem I'll let you know.
Jim

 

I got money on the UBEC. Underhood bussed electrical center aka the fuse box. We have had many many gremlins surface through the years as a result of bad UBEC's and they are notorious when you see as many of these trucks as we do.

I would start by checking all of the grounds on the block. But I can almost guarantee you it will be the UBEC. I'd start there and replace it after grounds and can almost bet it will solve your problems.

I have had ignition switchs from time to time but because the keyless entry has no bearing on the ignition switch that kinda shoots that one out of the water from a tech troubleshooting point.

 

01WS6/tamu
When you say replace it (UBEC), do you mean the junction block with the two release levers on it or the whole thing??

Thanks for the help.

 

GMJim, I've got a 08 Yukon XL at work doing similar things. TAC has escalated the case but because it's not warranty we get no engineer. Just @ random times it is like the battery is dead. Then others a no start but guages are bouncing all over and such. Negative battery cable replaced, all positive cables except to starter replaced, UBEC replaced, battery is newer (6 mo old GM/Delco). Checked, cleaned and torqued all 22ish grounds for the truck. Cannot duplicate in the stall, only when cust has truck. LMK what you come up with. It's coming back in Tuesday as it no started today.

 

In for an answer as well!

 

I've had a similiar problem with another truck used to have, not with locks or radio mine would just shut down out of blue no power to anything, no juice from battery, I thought same thing was the fuse box out of all the trouble shooting it ended up being a cross threaded bolt into the battery on the positive side walmart in there infenite wisdom cross threaded the bolt into the battery, I changed it out myself and never had a problem till I sold the truck, I hope this would help might be cheaper just to change battery and find out.