Security lock light steady on?

SINISTERFIVETHREE

MEMBER
2011 CHEVROLET TAHOE
5.3L
V8
4WD
AUTOMATIC
200,000 MILES

So here we go haha, I got out of my truck the other night after driving it, then got in it the next morning to start her up and nothing. The lights in the dash turn off and that's it no crank. So, I started my process, checked all fuses. Changed ignition switch changed the lock cylinder and keys, changed the anti-theft module and still this light is on. Also, while doing the relearn light does not budge before, at, or after the 10-minute mark. I am at a complete loss and at my last nerve, haha. Any suggestions?

7 Replies

JACOBANDNICKOLAS

MECHANIC
109,747 POSTS

Hi,

If it isn't responding to the ignition being left on, something other is happening. What I would suggest is to scan the can-bus to see if there are codes on other modules.

CAN stands for controller area network. Basically, the different modules are tied together via a few wires. This type of scan should retrieve codes from any module storing them.

Here is a link that explains how it's done:

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Let me know if that is something you have done or can have done.

Take care,

Joe

Note: I'm assuming the battery is charged and the terminals are clean and tight.

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Monday, May 22nd, 2023 AT 8:42 PM

SINISTERFIVETHREE

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4 POSTS

Yes, sir battery was hooked up while performing and yes terminals are all good. I was finally able to pull a code from the BCM it was B-1380-06. Is this referring to the ignition switch harness? And thank you for the wisdom Joe.

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Tuesday, May 23rd, 2023 AT 12:03 AM

JACOBANDNICKOLAS

MECHANIC
109,747 POSTS

Hi,

The code indicates an ignition accessory circuit short to ground or open. If you look below, I attached the diagnostics for this issue. Also, it provides a better description than I can. LOL And yes, it is related to the ignition switch. Actually, the switch is likely the issue, but testing will confirm.

Take a look and let me know if you are comfortable performing the tests.

Take care,

Joe

See pics below.

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Tuesday, May 23rd, 2023 AT 8:39 PM

SINISTERFIVETHREE

MEMBER
4 POSTS

Joe, do you happen to have a schematic or diagram for the ignition switch connector to BCM? I will definitely run these tests as well. I finally got the code off the BCM, and it hasn’t come back, yet still solid anti-theft lock?

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Wednesday, May 24th, 2023 AT 2:11 AM

JACOBANDNICKOLAS

MECHANIC
109,747 POSTS

Hi,

I do have them and attached them below. If you look at the first two pics, that is the wiring schematic for the anti-theft. The remaining pics are for the body control module, and they do include the ignition switch.

Note: To make the pictures readable, I had to cut each pic in half. For the anti-theft, there was only one page. The body control module was three pages.

I did overlap them so you can follow from one to the next.

Let me know if this helps.

Take care,

Joe

See pics below.

Images (Click to make bigger)