Trailblazer No Startup

[TexazReece]

Hello all well I tried to tackle my no start issue and found out it wasn't the starter. Mechanic checked it out but when he hooked up his tester it was showing that when trying to start the starter ignition relay was not switching from off to on. He hooked his tester his tb and he showed me his ignition was getting the proper 12 volts and mine was only getting 5 to 5.5 volts. I was told this is a computer/electrical problem. I wanted to see if anyone had thishappen to them before or what should I do?

 

[gmcman]

I haven't had what seems to be the inevitable ignition switch failure yet but I would think this could be the culprit.

 

[The_Roadie]

Certainly it's an electrical problem. When you say your "ignition", what specifically was he reading? Was he using a scan tool to let the PCM tell him by way of a data message what it thought the voltage was? Or did he properly hook a meter to some wire and look at it directly.

Using the PCM to tell you what voltage it "thinks" the vehicle has is not a valid or complete test. A simple loose or corroded ground connection on the fender to the PCM could give you that result.

And what's the "ignition relay" specifically?

 

[TexazReece]

I will have to check those ground locations to see if they aren't lose or corroded. Funny thing is when we were looking at the voltage going to the starter/relay it was at 5-5.3 volts then all of a sudden it bounced up to the 12-13 mark then started.

 

[TexazReece]

Certainly it's an electrical problem. When you say your "ignition", what specifically was he reading? Was he using a scan tool to let the PCM tell him by way of a data message what it thought the voltage was? Or did he properly hook a meter to some wire and look at it directly.


And what's the "ignition relay" specifically?

I'm sorry but I don't know the name or type of diagnostic machine he had but I know it was a snap-on. It showed pretty much everything you could check on the vehicle though. It did show the voltage for relays, battery etc. He showed me the difference when the ignition was off, when turned to on position and compared to his truck. Sorry Roadie but I may have put the wrong name for it but I remember it showing relay/starter rly. It also showed the relay harness was good as well as the ignition switch.

Sorry for double post

 

[TexazReece]

Could be fixed by purchasing another engine control module?

 

[TexazReece]

Checked ground connections which had no corrosion and were still tight. Another problem I forgot to mention is when the key is turned all the way I can't even try to put truck in neutral. Everything lights up as usual start up, lights are not dim at all but just won't start. Just nothing no clicking just nothing when key is turned.

 

[TexazReece]

Back to rollin' again

I remember what May03 had said in one of his vids about trouble shooting the no crank issue and singled out the problem. I knew I had replaced the ignition switch before so I was stuck on it not being the issue but remembered the saying always start small so work my way from the ground connections on up. Went on and bought a new switch to see what it would do and it started right up after replacement. So the previous one I replaced didn't last longer than a little over a year smh. I think I'll order an Acdelco ignition switch Monday as a good backup to the duralast sold by autozone. I'm just happy to be rolling again but a bit to late for the photo contest that just expired.

 

[Capote]

Great to hear you resolved your issue man [emoji41]

 

[KNBlazer]

I've always suggested AcDelco with these trucks, it's hit or miss if you get lucky with an aftermarket non AcDelco electronic part...