Yukon cranks but no start no dash warning lights or power to pcm or fuel pump

[Logan Scott]

Hey I have a 2000 yukon denali the obs style with the 5.7 I just developed a problem as of last night I went to drive it home from my shop for the weekend and she started right up no problems I backed it out let it run for a sec and shut it down so I could lock up. I've never experienced this problem with the truck before but when I went to start it again I had no dash warning lights when I turned the key to the run position and though it was weird but I tried to start and its just cranked no power to the fuel pump or the obd port I checked all fuses swapped and replaced ecm and related fuses and swapped starter relay. Just the basics I left the key on for a few minutes to see what happened and the lights came on after a while and the truck started and ran fine let it run and it stayed running but once I shut it down I had the same problem again so I cycled the key multiple time and it would start again then same thing once its shut down no power. It seems to always eventually come back on if I wait long enough does anyone have any ideas what it could be I've looked for a few hours on forums and Google trying to find someone with a similar problem but haven't found one exactly like mine im thinking maybe ignition switch? Any help would be appreciated!

 

[YukonGTmaster]

My guess would be the ignition switch as well. Have you tried playing with different positions on your tilt steering? Try it in “Bus Driver” and “How do I get my legs out” mode. See if the condition changes. Could be the ignition switch wiring harness is giving up the ghost.

 

[exp500]

Check Fuses Again.May be fuse block. Look at Circuit diagram and find where power should be. Test light usefull here.

 

[alpha_omega]

Hey boss did you ever get your problem solved?
If not, have you checked all of the ground to body connections (cleaned, dielectric greased and retightened them)? Additionally, have you ensured the post on your battery is tight, they can cause these kinds of phantom issues just as a loose coil/plug wire can - make sure they are all fully seated.