GMC Troubleshooting Questions? Ask a Mechanic for Answers
I am sorry your having this problem
does it act up enough to do a few tests with a multi meter or test light ?
this issue can not be a security issue as when the security system is activated it will NEVER stop the engine from cranking over
it will just shut off the fuel injectors
then these will NOT crank over physically with a new starter and the battery cables are clean and tight these issues come down to a bad starter relay or terminals for the starter relay or bad ignition switch
the ignition key or lock cylinder itself should not be causing this issue
no as the security system will never stop the engine from physically cranking over it will just shut off the fuel injectors when triggered
'if it is not cranking over physically it can not be the security system and most of these we have had with this issue where ignition switches or the starter relay or the terminals in the under hood fuse box the starter relay plugs into having bad connections and neutral safety switch failures on the drivers side of the transmission not telling the system the van is in park when in fact it is in park
if you can get it to act up we need to know if your fingers are on the starter relay when holding the key to crank do you feel the relay click with your fingers when turing the key to crank ? and also does the fuse called CRANK in the under hood fuse box show 12 volts when you hold the key to crank when it will not start ?
how are you making out ?