03 GMC 2500 battery problem

[donthekawguy]

Just picked up a RCLB 4x4 3/4 ton GMC with 105k on the clock. Drove it around for a couple days and everything was fine. We took it out to dinner and when we got home I started turning the headlight switch to see what the auto selection does. Nothing changed so I left the switch in auto. When I shut the truck off I pulled out the key and when I opened the door the dinger came on like I left the key in the ignition. I shut the door and the dinging stopped. I blew it off and went in. When I came out the battery was dead. I hooked up the cables and it fired right up. I let it run for a few minutes. I went out a few hours later and it just clicked like the battery had a little juice left. The ignition switch is a little loose and the headlight switch moves a little bit because its loose. I also was messing with the button on the switch so now I'll have to go thru and figure out what I did wrong. lol Any idea where to start? I did drive it to work tonight and it will sit for 12 hours before I try to start it so I'll see whats up in the morning. I'm thinking a bad ignition switch, bad battery or parasitic draw.

[hatzie]

Auto should shut off the headlamps when you turn off the ignition. That's the position to leave the headlamp switch in unless you want to turn em on during the day.
If the bell was dinging you likely had the headlamps switched on. That'll run the battery flat right quick.

[donthekawguy]

Originally Posted by hatzie

Auto should shut off the headlamps when you turn off the ignition. That's the position to leave the headlamp switch in unless you want to turn em on during the day.
If the bell was dinging you likely had the headlamps switched on. That'll run the battery flat right quick.

I could could hear the fan barely running when I turned the key on the next morning but I think I figured out the problem. The ignition switch is really worn out and sometimes I have to jiggle the key to get it to turn and to get the key out. I t did the dinging thing again when I drove it home this morning so I put the key back in and jiggled it until it stopped dinging. The original key is so worn out its hard to believe it can even start the truck. lol This truck was used by a landscape company for their sprinkler guy so it was probably started 20 times a day. It does have low miles and I would rather the guy wear out the starter than to leave it running all day. I have a new switch coming and also a cruise control stalk while I'm in there.

[hatzie]

I have a full set of all three lock cylinders with two keys that are in pretty decent shape... if I can find them. One Door, Ignition, and Spare tire lock cylinder.
They had 60K on them. I think they're in a box on one of the shelves in the garage.
I changed my locks as soon as I got it home. I had a truck stolen by the PO back in 1988 so I never leave the original locksets in my used vehicle purchases. You're most of the way across the country so they'll be a long long way from here and you'll have all the keys.

The hardest part is pulling out the LH outside door handle and that ain't too terrible.
It gives you a chance to spray the inner door bottom with 3M cavity wax to keep the rust at bay and re-attach any loose vapor barrier. And fix any loose electrical connectors and latch rods.

If you want to roll your own replacement lock cylinders I posted the howto details in my build thread.