Need Help or Suggestions for solving a intermittent electrical issue

[GremlinsinmyYukon]

Hi, looking for advice on how to solve an issue with my 06 Yukon XL Denali. This Fall it started failing to start after sitting in a parking lot in the hot sun. However it did start then a split second later cut out. I've been told that it sounds like a anti-theft feature causing it to cut back off. Also when it happens the Power locks, windows, radio and other features also do not work. I had it at a reputable mechanic for two weeks and they still did not figure it out. It got cold outside and quit acting up, so now I have to wait until spring or a rouge warm winter day. The mechanic thought it may be a shorting module in the heat taking down all the modules on the communication bus line. Oh yeah and the port to connect a scanning device also does not function when this event happens. No check engine light either. The mechanics plan was to disconnect the modules on the line one by one when it's acting up in hopes of it starting once the right problem module is disconnected. Any help is great, I would like to get this figured out before I get stranded again.

 

[Red Rider]

I would start at the obvious.. fuses. You could have a bad fuse that is causing some issues. I did not look at what was malfunctioning but look closely at the trouble circuits and see if they go to common area.

Also, look at any modifications that might have been done (non OEM radio, CB, other) that might have been poorly installed. If you don' t know what to look for, show it to GM mechanic (one who really knows your vehicle) and ask him if everything is OEM/stock.

 

[ccapehartusarmyINF.(ret)]

Check the fuel pump relay its in the same place as the fuses

 

[SLCHOE]

Hi, looking for advice on how to solve an issue with my 06 Yukon XL Denali. This Fall it started failing to start after sitting in a parking lot in the hot sun. However it did start then a split second later cut out. I've been told that it sounds like a anti-theft feature causing it to cut back off. Also when it happens the Power locks, windows, radio and other features also do not work. I had it at a reputable mechanic for two weeks and they still did not figure it out. It got cold outside and quit acting up, so now I have to wait until spring or a rouge warm winter day. The mechanic thought it may be a shorting module in the heat taking down all the modules on the communication bus line. Oh yeah and the port to connect a scanning device also does not function when this event happens. No check engine light either. The mechanics plan was to disconnect the modules on the line one by one when it's acting up in hopes of it starting once the right problem module is disconnected. Any help is great, I would like to get this figured out before I get stranded again.

Start there..