I have a 99 yukon won't start tried the
battery good turn the key lights work turn
the ignition nothing what could it be
These rigs have a problem with the battery cables corroding internally, so that is where I would start, pay close attention to the large red cable that goes from the battery to the main power distribution box. If that's not your problem then you need to start checking for power to the starter from the battery and from the ignition switch during cranking, could be a bad starter or ignition switch, you might want to check with the dealer to see if yours is involved with the ignition switch recall. HTH
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