No crank no start. And short with TBC#1 FUSE

Cody0426

Newbie
Original poster
May 25, 2022
4
Tupelo ms
I own a 2002 Chevy trailblazer 4.2 LS. My work truck i went to leave for work and no start. I have checked all fuses and relays. I’ve noticed my cluster hands are not working or gear selection indicator. My security light is not on. I have tested my starter pins also (jumped starter relay) and I have my 12 volts from my ignition switch 12 volts from my Nutural safety switch but, I’m missing the ground from my PCM. I used a test light, unhooked my ground and sure enough with everything off I had a direct short and amperage pull. So I started pulling fuses and then my test light went out when I pulled my TBC#1 fuse.. I also hear a relay clicking in my BCM
 
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Cody0426

Newbie
Original poster
May 25, 2022
4
Tupelo ms
Guess I should mention. When I go to start the vehicle it does nothing. All of my cluster/indicator lights go out but my headlights never go out. My break light and ABS lights are on.. Before the issue started there weren’t any lights on. My OBD port has power but vehicle will not communicate with code scanner that’s always worked up until the no crank no start
 

mrrsm

Lifetime VIP Donor
Oct 22, 2015
5,988
Tampa Bay Area
Since you are situated in The Deep South around Tupelo... Keep the possibility in mind that with the sudden appearance of this problem, Rodents may have gotten underneath the Hood and Chewed Away on some of your Harnesses and Electrical Connectors.

In particular, check over the Three Main Connector and Harness Bundles and Sheathing at the PCM. But don't limit your search to just one area down there... THESE are the Bad Signs confirming this Problem as THE Cause:

(1) Rodent Droppings along the Engine Air Plenum and underneath along the Valve Cover. Be advised... The Common Deer Mouse is a Carrier of the Dreaded HANTA Virus... so using an N-95 Mask and Nitrile Gloves when removing, vacuuming or cleaning out their Mess will be important.

(2) Signs of a gathering of Nesting Materials such as Hood Insulation, Animal Fur, Dried Grass and Pine Needles will all be packed in and around areas of the Engine Compartment.

(3)Chewed Plastic Connectors and finding desiccated Salt Crystals and Old Staining from Rat or Mouse Urine on any local surfaces. Beware the same HANTA warnings apply and responsibly dispose of all this Mess in Zip Lock Bags. Do not allow anyone to stand around while you perform any Clean Up - Vacuum Activities.

Use only Automotive Quality replacement Wiring along with proper Solder and Heat Shrink Insulation for any needed repairs. Replacements of any Damaged GM OEM Connectors can be obtained from TBs & Envoys from any Local Salvage Yard.

Also... Amazon carries Peppermint Oil Anti-Mouse Rodent Pouches that can be spread around into the "Nooks & Crannies" under ethe Hood afterwards to discourage "The Return of The Rodents". There are plenty of Proof of Concept Videos on YouTube that PROVE this tactic will work.

Be Suspicious ...Use a Bright Flashlight and REALLY look things over and you might solve this Disabled SUV Problem a lot sooner than you think. Many Other Members will have even Better Ideas on what to do next...
 
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mrrsm

Lifetime VIP Donor
Oct 22, 2015
5,988
Tampa Bay Area
One other "Quick Check" worth doing in this unusual electrical failure is to visit the Under Hood Fuse Panel and Lightly Re-Tighten the Zinc-Coated Fasteners that hold the Under-Connectors to the Fuse Block and re-establish better connections for all of them.
 
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mrrsm

Lifetime VIP Donor
Oct 22, 2015
5,988
Tampa Bay Area
One Other Honorable Mention...

Will Robinson's Classic "How To Diagnose and Find THE Failed Class 2 Network Module that Brings the WHOLE SYSTEM DOWN" is worth watching From START to FINISH.

The information he provides herein will let you take the entire Class 2 Network Off Line at the Front & Rear Class 2 Network Splice Packs and then systematically Add in One Module at a Time on "The Net" to discover Which One is FUBAR, Which One is Shorted HIGH (above 0-7 Volts DC) or Which One is Pulled Low and Shorted to Ground.

Download, Save and Observe THIS Training Video as often as needed to Discover that while having a Tech 2 Scan Tool and a Basic Oscilloscope is Very Helpful in this process... You can STILL achieve the same results and obtain a successful Repair Outcome on your Trailblazer or Envoy using Will's Other Manual Methods!

 
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mrrsm

Lifetime VIP Donor
Oct 22, 2015
5,988
Tampa Bay Area
If it comes down to cases... and you have to investigate "The Bag Of Snakes" that the Fine Wires inside of the Three PCM Wire Bundles becomes after removing their Sheath Protection... Having the PCM and BCM Pin Out Identification Images will help you to isolate the involved Shorted Circuits and ensure that the correct Re-Connection and Soldering and Heat Shrink Insulation can take place.

Start with THIS Link created years ago by @Realism which covers ALL Ground Locations for the GMT360s that SHOULD be investigated FIRST around the Engine Block in particular and WILL prove useful in No Crank No Start Events:


THIS Thread has ALL of the Important Links to the Ground Locations, PCM and BCM Pin-Out Diagrams necessary for Wire Tracing and Circuit Continuity Checks that may need to follow on during your Diagnostics:

 
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Cody0426

Newbie
Original poster
May 25, 2022
4
Tupelo ms
Yes sir.Thanks,and tomorrow I will get on it the minute I get off work. I don’t own a tech 2. The time I’ve put into diagnosing with no Answer I may go ahead with getting one. Will reply back tomorrow evening with what I find and again thank y’all
 
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mrrsm

Lifetime VIP Donor
Oct 22, 2015
5,988
Tampa Bay Area
Cody... Be SURE to Check out and Read Up On... (especially the last few pages of Posts) at THIS Link concerning ALL of what you need to know about either getting a "GYMKO" (General Motors Knock Off) Tech 2 ...or choose instead to get either an MDI Scan Tool or a VXDIAG NANO Scan Tool; all well covered over in other Threads in the Tech 2 Section:

 

Cody0426

Newbie
Original poster
May 25, 2022
4
Tupelo ms
Sorry for the delay in response but after complete interior removal main wiring harness had rubbed the frame aprox 15-20 wires were showing copper amazing I never had a single fuse blow but after some solder and compression couplings I can say it is as good as new thanks y’all for all the help y’all don’t know how much it helped I will be a member for life thanks again
 
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mrrsm

Lifetime VIP Donor
Oct 22, 2015
5,988
Tampa Bay Area
For those of us ever Investigating these "No Crank - No Start"
problems in posterity... The First Thing we always seem to do whenever so many things go sideways on our Trucks, SUVs or Passenger Vehicles and they Just Will NOT Start... is to Open Up The Hood.

Note the Mouse Nest hidden under the Fuse Box:

GMT800MOUSENEST1.jpg

...and the Chewed Wiring:
RODENTSGNWATWIRING0.jpg

BUT BEWARE... Once you lean over everything down there, you might be exposing yourself to Breathing In or Touching and getting Infected with the Dreaded HANTA VIRUS carried around in the Dried Feces, Desiccated Urine and Contaminated Nesting Materials as well as that Crap left upon surfaces nearby ...all covered with a Greasy, Rodent Residue.
MOUSEFECESNURINE.jpgMOUSEFECESNURINE1.jpg

Back in the Early 1990s in areas of the southwest in the USA, people appeared at Local Clinics and Hospitals bearing symptoms similar to that of COVID-19 but actually suffering from a Hemorrhagic Fever of Unknown Origin.

It killed almost 40% of its Victims and left the Survivors debilitated for years afterwards... and took a lot of time and effort to finally discover that it was caused by people Inhaling Airborne Dust and Dirt contaminated with the Feces and Urine of The North American Common Deer Mouse.

THIS is what we should all be aware of... and Avoid Touching or Cleaning areas under the hood that bear THESE artifacts of Rodent Infestation. MASK UP AND GLOVE UP FIRST, IF YOU CAN SEE THIS HAPPENING:

Is that ...Eric "O" from SMA holding a friable, dried up Dead Mouse in his Bare Fingers? Yup... So even the BEST of us still need to Be Very Careful whenever cleaning out this Mouse and Rat Mess from Under Our Hoods!

ERICOHWITHMOUSE.jpg
 
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