99 Silverado security light /no start.....

Hey hows it goin?My name is Josh,I have a 99 Silverado ext.cab LS 5.3 4l60E,and come to find it has the dreaded no start/light on.:shakehead Ive had the truck for about 2 weeks when i got it it needed a tranny rebuild.It has 160000 on it,by looking at it you cant tell.I couldnt even drive it when i bought it,so that was kinda scary.But it looked like it had been taken care of and the engine ran great and smooth......When i got it back from the tranny guy it ran fine,no problems.I was at work getting ready to leave i got in and cranked it over but nothing.I ran home to get some cables to jump it.That took about 10 15 minutes,so i guess it reset itself.By reading old posts it seems like im not the only one.The security light comes on while driving only sometimes,but its happening more often.I dont like the feeling of maybe it will or wont start.I want to try to fix this myself without making it worse.I have also read about it on alldata .Is it the ign.switch?Is it possible to take it out and clean it?I want to do it right the first time.Thanks for all your help.I love my truck and want it back to normal.:wink:

Hey hows it goin?My name is Josh,I have a 99 Silverado ext.cab LS 5.3 4l60E,and come to find it has the dreaded no start/light on.:shakehead Ive had the truck for about 2 weeks when i got it it needed a tranny rebuild.It has 160000 on it,by looking at it you cant tell.I couldnt even drive it when i bought it,so that was kinda scary.But it looked like it had been taken care of and the engine ran great and smooth......When i got it back from the tranny guy it ran fine,no problems.I was at work getting ready to leave i got in and cranked it over but nothing.I ran home to get some cables to jump it.That took about 10 15 minutes,so i guess it reset itself.By reading old posts it seems like im not the only one.The security light comes on while driving only sometimes,but its happening more often.I dont like the feeling of maybe it will or wont start.I want to try to fix this myself without making it worse.I have also read about it on alldata .Is it the ign.switch?Is it possible to take it out and clean it?I want to do it right the first time.Thanks for all your help.I love my truck and want it back to normal.:wink:


Is this an engine cranks and does not start or a engine does not turn over concern?
Is the security light on steady when you try to start the truck?
Any other lights on?
What was wrong with the trans that it had to be rebuilt?
Do all the guage or dash warning lamps illuminate like they are supposed to when you turn the key to run?

A security light in a GM vehicle normally means the wiring to or from the lock cylinder is damaged.It's best to replace rather than repair the wiring because the wires are so small and break easily.

Hey guys thanks for the help ,the tranny had a tooth from the planetary gear that must have broke off and slung around in there.I got it rebuilt and works great.The engine cranks and wont start.Has plenty of juice.All the gauges and lights come on like they are supposed to.when i first get in the security light will blink till i shut the door,then it will stop.when i put the key in and turn to run i will see the battery light and then security which usually goes off while cranking.if it starts, some times the light will stay off then come as im driving.or it will stay off.It has been running fine for me for two weeks and now this is happening more.If it ends up starting it will run fine,like nothing ever happened.Only does this sometimes dont know when it will.When i got it from the tranny shop it ran fine no problems.????Hope this helps guys.

When the truck will not start, does the MIL light come on when the key is in the run position?

With a cranks and no start, we have to find out what is missing from the equation (spark or fuel)
A Security problem will cause a start / stall condition...the security light coming on while driving indicates there is something going on with the passlock system, but I don't think that is going to be the reason your engine cranks and won't start at times.
You can go to Autozone and have them attempt to pull codes out of the PCM.

Hey GM Merlin thanks for getting back to me,the mil light will come on for a second than turns off.My Dad has a scantool and it isnt sending any DTC codes .Yesterday morning when i left to work it started up and ran fine nothing unusual i made a few trips in it throught the day and it did what its supposed to do.I checked all the fuses crawled under the dash and made sure everything was n order.
When this started happening i was reading old posts and it seemed to me this was a passlock problem.If the ign needed to read the resistance of the key,then my key probably wasnt good enough.It was really loose in there,worn out.I ordered some oem keys and they came yesterday along with a new keyless remote.I went out and programmed the remote went to get the keys cut and they fit like a glove.Like that was the key meant for it.Not loose at all.It hasnt been acting up for two days......but it ran all that day with no problems without the new key so..Its a start stall like the injectors r bieng cut off by passlock.Its getting plenty of fuel and spark.If it ever doesnt start i will wait 10 15 minutes and it will fire up.We will see today when i head to work.I will update when i get home tonite.:banghead: Thanks again.

OK now we are getting somewhere.
A Start/stall is usually a good indication that what you are experiancing is a theft deterent concern.
Good call on the keys, that may have something to do with it.

Hey GmMerlin,well it has been three days and it has been fine.No security light starts everytime.IM wondering if the key helped.I was talking to this tech that i tattoo on and he talked to one of his buddies and he said that the loose key might of been shorting things out,wiggling around in there?I hope that was it.I dont know i guess we will see.Thanks for your concern with my truck,i will ket u know what happens. Josh:evillol: