Problems with 2003 Chevy avalance

Scan for trouble codes. Then, before replacing anything go through (or have someonewho specializes in auto electrical do it) the entire electrical system to make sure all connections are clean and tight. Then scan again and see if anything has changed. Don't forget about the various ground points in the system. In fact that's actually where you should start. Once you've got that taken care of then consider replacing components if that seems to be what's called for.

Thanks I had it scanned at auto parts place and no codes.Ran fine yesterday and this morning.Got in and seat not moving.Then this afternoon won't start.Going to have another scanner from shop.dianostic scan.Least I'm at home.Appreciate the reply.

With no codes it makes me even more inclined to think its just weak or faulty electrical connections or grounds. Older electrical systems are prone to that sort of thing and are so sensitive to even minute voltage drops and interruptions. I have a tech who specializes in that sort of thing and he's worked miracles with several of my vehicles just by cleaning and tightening connections. That said there are a few problems that have left him scratching his head too. All my vehicles are older and in some cases high milers as well although I think it has more to do with age than mileage in most cases. My "04 Avalanche seemed like its electrical system was haunted when I first got it. An aftermarket security system that I didn't know it had was causing most of the probelms. Once that was gone it was much improved. I finally gave up on some of the settings like the power seats etc. and the mirrors on mine went crazy from time to time and still do. It's an old truck with 320,000 km though so some of that we just live with. I understand that in your case you can't just live with a vehicle that sometimes won't start. I know there's not much in the way of helpful information here. If the sort of trouble shooting I'm talking about is beyond your skill level like it is beyond mine then try to find a shop that specializes in this sort of thing and they can probably clean it up enough to get the truck through the balance of its life. A tech who understands how all that stuff works is worth his weight in gold.

It cranked right up this morning.Talk to the shop and man said diagnostic test wouldn't help so at least I don't have to pay for tow or test.Just hope he finds the problem.Noticed yesterday when it wouldn't start I could hear something in steering column.Maybe it's the ignition sensor.I don't know but they come recommended.Figure best thing to do is bring it in.Least when they start talking about what I need I will know where it's located and how detailed the work will be.Appreciate your info.That noise kinda leads me to think ignition switch sensor though not a mechanic lol a utube.Least I know the sensor located on column and no steering wheel has to come off.Hoping for a reasonable price also.Thanks so much for replying back and the info.

Yes a good tech is worth their weight in gold.I surely hope I got one.

Possible bad ignition switch.

Appreciate the reply.Hoping it's not much.

Took to shop and they can't find nothing.Sais putting on machine won't help.been there three days and man said they run it and nothing.then tried to say it was empty and had to put gas in then it cranked just fine.keep it full and told him that then he said put in 7 and showed full.maybe fuel tank sender not working because was empty.I took the truck home.On the way stopped and filled up took 10 bucks.waited a few minutes and tried to fill more but it only took 50 cents.Not sure but figure if he thought it was empty and 7 filled it up just might need to go.Going to try and find a machine that might would read electronics.Acts like no fire.no fuel when it wont start.Yep headaches for sure.Wondering if ignition sensor could cause these things and no start.