2008 yukon xl. All lights come on shifting hard at times and doors lock & unlock while driving

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Jan 19, 2020
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#1
Make
Yukon xl
Model
Gmc
Year
2008
Miles
169,000
Engine
5.3
I have a 08 yukon xl. Sometimes while driving it flashes light, gauges go crazy, doors lock & unlock and transmission gives a hard shift and sometimes holds gear. I have change the mega fuse and the bcm. Im stumped on what to do next besides a new ecu. At times truck don't show an indicator light for gear and won't start. Can you give suggestion before i buy a ecu.
 

grcauto

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#2
Go through the grounds.
What is the mega fuse and why did you replace the BCM? Did you have it programmed?
 

jigfeett

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May 30, 2008
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#3
I second GR grounds run the entire vehicle you might think it is power but it isn't. You can have all the power in the world but if you don't have ground, the power looks all over the place for a ground and it will usually find it but then other things go nuts. Test with the direct battery ground and never a painted part.
 

EricC

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#4
Have you checked it for DTCs yet? Multiple DTCs, especially trans codes (P07XX) could be an indication of a faulty ignition switch. I wouldn't replace anything else until you get it diagnosed.