2005 sierra duramax wont crank over

[born-to-fish-]

Took my truck in to get the coolant and thermostats changed and after that it wouldn't crank over..period.

 

My first thought was the batteries were toast as they're almost ten years old. I tried removing them, charging them up

 

but they failed a load test. So now I've replaced the batteries with two brand new ones, and it still wont crank over.

 

Swapped the relays around as my first guess, no difference. Can bypass the relay and it will crank over.

 

Checked the neutral safety switch, it still is indicating the gears as I move through them. One other thing the mechanic

 

said was he couldn't communicate with the truck using his scanner, but that was with the old batteries. Haven't tried

 

scanning with the new batteries. When I turn the key on the security light comes on for a few seconds, then goes out. The only

 

indicator I see on is the check engine light, but that stays on until it starts I think...? Don't think its the security locking me out, as that

 

would make the truck still turn over but not start, as if it was out of fuel.

 

Any help on this matter would greatly be appreciated.

 

Thanks,

 

Kev

[Prokopchuk_9]

Get a scanner on it, could be a fuse blown too to get it scanned.

 

When bump start it does it fire up? Or just crank the engine?

Another question...why isn't your truck back at the shop it was at to get it fixed? If it ran fine before why not now? Tell them to do their jobs

[born-to-fish-]

When I jump from pin30 to 87 on the starter relay, it cranks over fine but wont run.

 

Checked the fuse (cig lighter) and it's fine.

 

Don't want to take it to where I had the coolant changed, as they're at a loss as to the problem,

and they seem like a bunch of muppets anyhow, as they couldn't even recognize the battery

problem, nor wanted to put new batteries in it, as he didn't want to wreck two new batteries.

They haven't charged me a dime for the coolant/thermostat work and wanted to tow the truck

off to another "electrical expert". BS! Seems they're trying to wash their hands of this problem, as

they're convinced they did nothing wrong.