tbb2

Failure hit me out of no where.
No previous symptoms except for maybe the necessity of jiggling the key to get the ignition to turn. This may have been a worn key. Or is this more important than I yet suspect.

Have been driving for years since solving a parasitic drain without issue.
A couple of days back I went to a gas station to fill up and when I got in and turned the key to On - everything normal - then to Start and nothing happens except the dash lights go black.
I checked the battery and it had 12.58v so I should at least have had dash lights.
The service station mechanic came out with a portable jump starter and after three tries the engine cranked and started.

At home and parked the same no-start no dash lights condition exist.
I record a 0.450amp parasitic drain through the negative battery cable. I disconnect the battery cables.
Van sits over night. I connect the battery to attempt to start and same ... key to On - everything normal - then to Start and nothing happens except the dash lights go black.
I record the battery is at 12.41v and now a 1.13amp drain through the negative battery cable.

I hook a charger to the battery and it goes to 6-8 amps and drops to one amp after a minute plus.
The headlights, parking lights, hazard lights and cabin light illuminate.
This tells me the battery is okay.

Over several days I checked all the fuses I suspect are part of the ignition system and they test good for continuity.
I record the battery is at 12.41v and now a 0.001amp drain through the negative battery cable. So the parasitic drain has stopped and so have any dash lights.

I am looking at no-start videos and going through the checks.
I checked the starter relay and it bench tests positive. I checked the starter solenoid for continuity from the S terminal to starter casing and S terminal to start connection post an both check out as positive. I have continuity from the positive battery cable to the solenoid bolt.
So far having the dash go black is only referenced to a bad battery.
It strikes me something has burning out but how do I narrow down the system?
I was reading a post for another electrical start problem but do not understand the acronyms ... PCM (power control module?), can bus issue?, ECM?, BCM?, TCM?

Some direction will be appreciated.
Thank you

mountainmanjoe

1mA drain is normal. But 12.4V is too low.
Get your alternator checked for free at Autozone

tbb2

mountainmanjoe,

I agree 12.4 is low but that is after the problem started.
Wouldn't I have dash lights of some kind?

tbb2

mountainmanjoe

you should have dash lights. Check fuses/relays/ignition switch.

William Kisselstein

Examine the ground cables. Possible one is corroded or failing in some way. Won't allow enough power to pass through to start the van.

tbb2

mountainmanjoe,

Do you have a reference for checking the ignition switch?

tbb2

mountainmanjoe

The yellow wire should get energized when you turn the key.

If you're going to be fixing things on your van yourself, then I highly recommend getting a repair manual you can sit down, study, and ponder over. (eg Haynes). It has step-by-step instructions for disassembling everything, electrical schematics, common problem troubleshooting etc.. They are worth every penny!

Also, you should always check for relevant technical service bulletins (TSB) for your vehicle. For example this one regarding inoperative instrument cluster.

https://www.tsbsearch.com/GMC/01-07-30-002E/612

Powertrain Control Module (PCM) controls an engine and transmission.
Sometimes they are separated: Engine Control Module (ECM) and Transmission Control Module (TCM)
CAN bus = how the modules talk to each other. (like USB on your computer)

tbb2

I have the 3 volume 2003 Service Manual. They have paid for themselves so far but not helping me now.
Organization was not the writer's strong point. The organization of information seems to be based on reading from cover to cover and remembering it all.
I have to wonder if the wiring diagrams were intentionally disconnected so they could not be followed. The draftsman must have never heard of a GoTo Note or Match Line.
If I flip through enough pages I can eventually find a fuse # that starts a page that is the same from a page it ran off of.

I have not yet found the ignition switch section that deals with "removal, Installation or diagnostics".
The index does not call it "ignition switch", "starter switch", or anything under "switch". It is not under Wiring Systems or Engine Electrical.
I have found multiple wiring diagrams in different volumes.

Thanks for the Link. It does call out something else to check.
"The most likely cause of this condition (Instrument Cluster Inoperative) may be a loss of voltage to the transmission solenoid power supply circuit."
... Assuming I can find it.

mountainmanjoe

That's a shame

Did you check under Steering Column?

I believe the "run" wire from ign switch is yellow. So test if you get steady juice on there, and make sure you jiggle the key around too.
I would test ALL your fuses. Sometimes they're connected in unexpected ways. And use a light or meter because blown fuses sometimes look ok.
When you say dash lights, do you mean only the instrument panel, or the entire dash (radio, HVAC controls etc.)?

tbb2

As much as I did not believe the battery would just roll over and die ...
the battery did just roll over and die.

Voltage AND CCA both are necessary tests to determine the health of the battery.

I do not know what to make of the drain numbers I measured after the failure except they may have had something to do with the batteries death rattle (?).

A new battery put everything back to operating normally.
I am reading a 0.70 mAmp drain on the battery which at this point I assume is running the clock.