Car won’t start, doors won’t lock or unlock from inside or fob

[benjaminblazer]

I was driving home and all of my dash lights turned on and my info gauges on the right all went to 0 or all the way to the left. The car ran fine but when i can back home the car will not start, headlights still work, accessory mode works, stereo doesn’t turn on, etc. I replaced the ignition switch and same thing. Battery rests at 12.4 and charges at 14.9. Any ideas??
2006 Ls Trailblazer 4wd

 

[mrrsm]

Welcome to GMT Nation:

(1) Check for a Bad Ignition Switch and R&R it if necessary with an OE Quality One.
(2) Check the Battery Condition (LOAD Test) and Battery Cable Connections.

An event with identical symptoms to your situation is mentioned at the Link below:

Dash lights came on and gauges dropped to zero chevrolet ...

Q: When driving, occasionally all the dash lights will come on, but the gauges like gas, battery, and mileage, will all drop down to zero. Then my radio shuts off. Fortunately, the car keeps driving. All of this happened today,...

www.yourmechanic.com

 

[benjaminblazer]

Welcome to GMT Nation:

(1) Check for a Bad Ignition Switch and R&R it if necessary with an OE Quality One.
(2) Check the Battery Condition (LOAD Test) and Battery Cable Connections.

An event with identical symptoms to your situation is mentioned at the Link below:

Dash lights came on and gauges dropped to zero chevrolet ...

Q: When driving, occasionally all the dash lights will come on, but the gauges like gas, battery, and mileage, will all drop down to zero. Then my radio shuts off. Fortunately, the car keeps driving. All of this happened today,...

www.yourmechanic.com

I replaced the ignition switch already and same result unless i got a bad one i don’t think it’s the switch. I got an autozone duralast part.
Also tried multiple batteries making sure connections were great plus i have the big 3 upgrade for grounds and alternator positive post wire.
Checked all fuses, unless they gave me a faulty ignition switch i’m not sure.

 

[budwich]

what do you mean "will not start".... nothing happens or the engine turns but doesn't start? IF you are getting no "start action", then check the connections at the starter for voltage and ground. Check the starter relay in the fuse box.

 

[benjaminblazer]

what do you mean "will not start".... nothing happens or the engine turns but doesn't start? IF you are getting no "start action", then check the connections at the starter for voltage and ground. Check the starter relay in the fuse box.

I mean nothing, no crank, engine definitely doesn’t turn on. When key is in accessory mode i see an airbag light, ABS, Engine light, battery light and parking brake light stay on. Doors will not lock, windows don’t work, i feel the starter relay has nothing to do with the doors and windows yk. Will do tho👍

 

[budwich]

OK... you have a lift gate module issue... most likely broken wiring.

 

[benjaminblazer]

Where’s that at? can i check it out to make sure?

 

[benjaminblazer]

OK... you have a lift gate module issue... most likely broken wiring.

Never mind I'm guessing the tailgate harness that looks like this.

 

[budwich]

the wiring gets brittle over time and the open / close causes issues from "no power" to sporadic operation / messaging, etc. You will need to inspect carefully as quick visual looks may not find broken internal wiring of the cables.

 

[benjaminblazer]

the wiring gets brittle over time and the open / close causes issues from "no power" to sporadic operation / messaging, etc. You will need to inspect carefully as quick visual looks may not find broken internal wiring of the cables.

Could it for sure be this or could it possible be something else? Have you seen this happen before because i feel i have tested so much already but i know it’s impossible to figure it out sometimes with electrical problems.

 

[budwich]

there is no "guaranty" on internet troubleshooting. Your success will depend on your effort AND how well you describe what you have done and what you see as YOU are the eyes and hands for the forum.

The circuit for the start system is relatively simple. Follow it to check what is happening. Go from the result of the investigation therein.

 

[benjaminblazer]

there is no "guaranty" on internet troubleshooting. Your success will depend on your effort AND how well you describe what you have done and what you see as YOU are the eyes and hands for the forum.

The circuit for the start system is relatively simple. Follow it to check what is happening. Go from the result of the investigation therein.

Everything in the back looked well, took off the whole panel and followed the grommets i’m not sure tbh

 

[benjaminblazer]

there is no "guaranty" on internet troubleshooting. Your success will depend on your effort AND how well you describe what you have done and what you see as YOU are the eyes and hands for the forum.

The circuit for the start system is relatively simple. Follow it to check what is happening. Go from the result of the investigation therein.

Did some searching could not find anything loose or suspicious with wiring in the back. However my obd2 reader will not even connect to the car when the car is in accessory mode. I have voltage to the scanner port but won’t read. i’m concerned it might be the ECM but some say you can’t drive when that goes bad and i drove for a good hour and a half after.

 

[mrrsm]

Check Out Will Robinson's Signature Thread - Video on "How to Investigate the Class 2 Network" for Instructions on how to take down ALL of the System Modules that use the Network at the Two Splice Packs:

One under the Driver's Side Dash Kick Panel...



And... One under a Carpet Flap beneath the Rear Passenger Side Seat...



Then, following the scientific idea that you should, "Only Change ONE Variable at a Time"...Follow Will's Step-By-Step Instructions for How to Test and Bring each Individual Module Splice Pack Connection Back On-Line ...gradually... until you find the Problem Module.

THIS Video is a *Keeper* that emphasizes the point that ANY Module can affect or Bring Down the ENTIRE Class 2 Network if it has internal shorts or other failures because... The Class 2 Network functions with ALL Modules communicating on a Single Network Wire.

 

[benjaminblazer]

Check Out Will Robinson's Signature Thread - Video on "How to Investigate the Class 2 Network" for Instructions on how to take down ALL of the System Modules that use the Network at the Two Splice Packs:

One under the Driver's Side Dash Kick Panel...
View attachment 111802

One under a Carpet Flap beneath the Rear Passenger Side Seat...

View attachment 111803

Then, following the scientific idea that you should, "Only Change ONE Variable at a Time"...Follow Will's Step-By-Step Instructions for How to Test and Bring each Individual Module Splice Pack Connection Back On-Line ...gradually... until you find the Problem Module.

THIS Video is a *Keeper* that emphasizes the point that ANY Module can affect or Bring Down the ENTIRE Class 2 Network if it has internal shorts or other failures because... The Class 2 Network functions with ALL Modules communicating on a Single Network Wire.

I actually ended up getting it started.. I turned the key to the on position then I turned my headlights off by switching the lever to the left. The car started probably 4 times. I then went on with life and came back to the car for the same problem. Windows, locks and everything were working now they aren’t. Tried the same thing but it won’t work. I’m at a loss of words. Was able to pull codes:
p0976

p0787

p0973

p2769

p2764

 

[mrrsm]

Post #5 in @Realism 's Epic "GROUNDS" Thread describes WHY this can happen to a "T" ...BECAUSE ... The Left Head Lamp...The Fuel Pump Relay AND The Left Turn Signal ALL share a Common Ground that will draw EXCESSIVE AMPERAGE and cause the Fuel Pump Relay to DROP OUT if that Ground (G107) is BAD:

Electrical Ground locations

While troubleshooting a bad ground I came across some scans of the service manual regarding electrical ground locations for our platform posted on another site. This includes both short and long wheel base, as well as both 4.2L and 5.3L. Credit goes to Wex...

gmtnation.com

:

 

[Mooseman]

Those are all transmission codes. We have lots of info on this problem.

Transmission with multiple codes
Another Transmission with Multiple codes
More Multiple Codes
The 5 Transmission p codes

 

[benjaminblazer]

Those are all transmission codes. We have lots of info on this problem.

Transmission with multiple codes
Another Transmission with Multiple codes
More Multiple Codes
The 5 Transmission p codes

Drove the car over 4 hours when i did get it to start, definitely not a transmission issue even tho these codes were present.

 

[Mooseman]

There's an issue with the wiring or.power to the transmission

 

[benjaminblazer]

There's an issue with the wiring or.power to the transmission

What wiring though, feel we checked everything😂

 

[benjaminblazer]

There's an issue with the wiring or.power to the transmission

Also would loss of power really not allow the doors to lock and unlock, windows and radio ?

 

[benjaminblazer]

Another update: receiving voltage on fuses 17,16 and when jumping starter relay car starts right up.

 

[mrrsm]

Try unbolting the Four Galvanized Post Fasteners holding the Harness Blocks to the bottom of the Power Distribution Center (Fuse Panel) then spray out BOTH sides with CRC Electrical Solvent and SNUG the arrangements back together again after they are Bone Dry:





On occasion... the Solid Copper Wire Traces fitted into the Plastic Inner Sandwich inside of the Power Distribution Center can *work harden* from engine vibrations and thermal variance... and Crack apart. With changing under-hood Heating and Cooling conditions... intermittent Starting and Shutdown Events can occur afterward.

There are several Threads here at GMTN that cover how to drill out the Four Connectors and gain access to that area. Then, by using a Bright Flashlight and a Magnifying Glass, such Copper Tracing Breaks can be located and repaired with Lead Solder. THIS is what this phenomena looks like:

 

[budwich]

check for powers and grounds at the bcm.

 

[mrrsm]

...AND... FUBAR'd Fuses...

 

[benjaminblazer]

...AND... FUBAR'd Fuses...

Took off the block all copper is fine, disconnected those splice packs and no change. Sprayed all connections and letting it dry now, sanded down any green connections as well.

 

[benjaminblazer]

check for powers and grounds at the bcm.

do you know where ground and power locations are for bcm ?

 

[mrrsm]

Definitely... These Attached Wiring Diagrams often prove helpful in finding the Proper Pin-Outs at the various connectors AND their Harness Color - Coded Wiring, too. Note that some of these Diagrams originated in other Threads as penned and linked by @TJBaker57 's Excellent Contributions.

THIS particular one is for the BCM.... The Source B+ Voltage at 12.6 Volts DC comes through and into the BCM at the C1 Connector Pin-Out A3 via a Solid Orange Wire -- HOT AT ALL TIMES --- reaching back into the Under-Hood Fuse Block on the C2 Connector protected there by the 10 AMP Fuse in Position 31 and ID'd as "TBC1" of the Power Distribution Center (Fuse Box) Layout Diagram linked above.

The BCM Unit Ground has its attachment point located at G302 on the Lower Left "B" Pillar of the SUV and it likewise feeds into the Body Control Module on the C1 Connector as a Solid Black Wire at the Pin-Out B11 and ID'd as "NCA" sharing its Ground with the Data-Bus Ground of S302 as per @Realism 's Epic Grounds gathered by @jmonica and shown in the attached PDF. You can see BOTH of these connections right on THIS Diagram below:

 

[benjaminblazer]

Thank you everyone for the help, found a grounded out wire behind the stereo.. idk how it affects the start of the car but sorry for wasting everyone’s time.

 

[mrrsm]

It's never a waste of time when the OP closes the loop by adding new knowledge. The next peeps facing this similar conundrum... will thank you for explaining what you've discovered. :>)

 

[jmonica]

...AND... FUBAR'd Fuses...

Yep. I can concur with this. I had a fuse that tested fine in the fuse panel /block. It looked fine (Not blown or burnt out) when removed, but one of the "legs" was broken in a place that you couldn't see the break, so it was causing an intermittent problem.

The lesson I learned was that if I have an intermittent problem on a known circuit, don't just test the fuse in place, but rather pull it out and closely examine it. I chased that problem for hours and just happened to find it by chance. I leaned over the engine compartment to do something and with my hand on the fuse block, I just happened to move the fuse in a way that caused it to disconnect (or reconnect I forget). Best of luck!