New marketplace truck, most of the electric does not work.

[Road Trip]

Happy Halloween folks! I come bearing good news! That is (what is left) of my radio harness! For some reason known only to god, the ground was cut out of it. I put a ring connector on and bolted it to the dash and suddenly my gauges seem to read mostly correct AND both power windows work again AND my HVAC screen has come back on and I can hear relays clicking around in the dash.

Just documenting what the orphaned harness connectors for the radio are.
(In case you ever decide to add a radio back in after you undo all the PO's
mischief.)

You must be registered for see images attach

And here's the Wiring Diagram that I used to identify the connectors in the photo above: (By matching up the wiring harness colors)

You must be registered for see images attach

Alright, that's pretty much all I got at this point. Tag, you're it!

Seriously, once you get the 4-way flashers running, the IP ground bypassed with a
fresh lead, and the radio wires taped up & stashed out of harm's way, then you can
share the new current status of the electrical system in your truck.

Possibly you still have a cross-connection between the CTSY fuse and some loads
that shouldn't be on this? But IF the only funky behavior left is just the underdash courtesy
lights staying on then maybe we just need to sort out the functionality of the door ajar switches?

Best of luck. If you succeed this will be several thousand pounds worth of
functional recycling. Who says that mechanics aren't green? :0)

Cheers --

 

[Erik the Awful]

Last night I got Roscoe's mouse-chewed harness out alongside a hacked up harness I got from Pull-A-Part and started splicing them together into a single good harness. I ran across C243 in that picture above and haven't taken the time to figure out what it went to yet. Talk about fortunate timing! Thanks!

 

[Road Trip]

My footwell lights are somehow connected to those stripped orange and yellow wires and connecting them, even without the CRTY fuse installed, turns the lights on.

04-Nov-2023 EDIT: As identified in the photo in post #41 above, the Orange wire belongs to the CTSY
circuit, and depending upon how I read the above, if you were to connect it to the nearby Yellow wire
with the key in the ON or ACC position, I would expect that the footwell lights would come on.

If the above is true, then feel free to skip the rest. All is working as advertised.

****

Hi Additivewalnut,

We've discussed quite a bit, but I don't think we've touched on this particular symptom. It sounds like the
'Hot At All Times' CTSY fuse-protected circuit has been accidentally cross-connected with another power source,
possibly powered up through the ignition switch?

This isn't a priority, but when you are winding down from the other fixes, I'd
be interested to know exactly when the 'footwell lights still coming on without the CTSY fuse
installed' symptom presents?

For example, IF the lights still come on w/no CTSY fuse, but only when the ignition is in ON & ACCessory,
then this narrows down which other power circuit has been cross-connected to the one that feeds your
footwell lights?

OR, if the footwell lights have power available ALL the time, even with the key out, plus the CTSY fuse not installed,
then we need to investigate further. Because this scenario might be caused by the PO jumpering around a fuse to
force something to work, (aka: idiotic move) thereby removing the intrinsic safety that these fuses provide us?

Taking this one step further, IF your footwell lights have power available 100% of the time with the CTSY
fuse out, I would want to know if these lights are on a fused circuit or not. No problem. It's as easy
as working sequentially through the fuse block, pulling one fuse at a time until the lights extinguish.

Worst-case scenario: And what if more than 1 power circuit is cross-connected, which can't be found by the
normal 'remove 1 at a time' search? Go for the gold, and pull ALL the fuses. The results will tell you
which way you need to proceed:

* IF the footwell lights now go out, good. Then start adding the fuses back in, one at a time, until the lights
return. Document that fuse, remove it, and continue to add in the remaining fuses, rinse, repeat until done.
This way you can figure out if it's 1, 2, or 3+ circuits that are cross-connected. Think failed/forgotten/hidden
aftermarket anti-theft device (installed by some PO) monitoring different electrical circuits for activity. Hunky-dory
until it breaks... (@Komet nailed this in his previous reply. :0)

Note: If the footwell lights stay on with ALL the fuses out, then this is an illegal** condition, and must be
figured out. Now you have to go back to the firewall, and disconnect the wires at the battery junction block
until you finally find which 'Always On' feed is responsible, and go downstream from there.

****

Again, this doesn't rise to the same level as an intermittent power problem involving the fuel pump. And
if you figure out the cross-connection but there's not time to actually fix it until later, then just remove
the footwell bulbs (and disconnect other non-essential convenience items on the same circuit) until you
can address the issue with a permanent fix.

The bottom line, the more we know, the tighter the problem definition, and the better we can
implement an appropriate measured response.

Wrapping this up, here's what the Courtesy fuse is supposed to support:

(Note: Substitute 'Glove box' for 'I/P Compartment' Lamp -- FSM jargon)

You must be registered for see images attach

And I've attached a couple of schematic pages showing the 'door jamb' switches
and the wiring that's supposed to be involved.

Last & least, there's no mystery to electric power distribution. Lots of details, sure. But no magic.

Happy Hunting --

**Electrically speaking. I'm not afraid of electricity, but I *do* have a lot
of respect for it. For me, an unknown power circuit mod under the dash = potential
fire hazard. IF I can make sense of the mod, I might decide to leave it in place.

But I've learned the hard way not to ignore janky-looking stuff from overconfident
sparky types that have preceded me. Safety first! :0)

 

[Additivewalnut]

Hello all, long time no speak. Took a break from my wiring to fix my non-functional rear brakes and fix the slop in my steering. Did some towing with it last night, even with 211k on it, this thing does pretty good! Weirdly enough, while cruising down the highway, for seemingly no reason my dash lit up and started working absolutely perfectly. Backlighting working with the dimmer, gauges reading correctly..... but after sitting overnight they've gone back to how they were where the headlights being on pegs out the gauges and I can control how they read with the dimmer. Something else of note, my trailer wiring is bad (big surprise) but around the same time the gauges came on, the trailer lights started flickering on and off. Tried jiggling the connector, disconnected it entirely, didn't make a lick of difference on the gauges last night as they would still work perfect. Attached pic is after the trailer was disconnected. Note the seatbelt light and the brights indicator being falsely lit. Wonder if that has anything to do with anything?

You must be registered for see images attach

 

[Road Trip]

Hello all, long time no speak. Took a break from my wiring to fix my non-functional rear brakes and fix the slop in my steering. Did some towing with it last night, even with 211k on it, this thing does pretty good! Weirdly enough, while cruising down the highway, for seemingly no reason my dash lit up and started working absolutely perfectly. Backlighting working with the dimmer, gauges reading correctly..... but after sitting overnight they've gone back to how they were where the headlights being on pegs out the gauges and I can control how they read with the dimmer. Something else of note, my trailer wiring is bad (big surprise) but around the same time the gauges came on, the trailer lights started flickering on and off. Tried jiggling the connector, disconnected it entirely, didn't make a lick of difference on the gauges last night as they would still work perfect. Attached pic is after the trailer was disconnected. Note the seatbelt light and the brights indicator being falsely lit. Wonder if that has anything to do with anything?

You must be registered for see images attach

Q: Have you had a chance yet to try to add those grounds like you proposed back in reply #38? (LINK)

Your latest observations about the dash suddenly working is a very positive indication -- lots of stuff
is able to work, but only when all that stuff doesn't have to try to work through a marginal ground path.
And with all the vibrations of a truck being driven down the highway, it makes sense that some of that
vibration may have (temporarily) helped to jostle a bit better electrical path in a nearly broken connection.

It really seems that there is an intermittent issue in factory splice S207, which your proposed additional
individual ground wires to the IP and dimmer circuit will either fix outright OR further our troubleshooting.

Dude, that's a heckuva nice looking nighttime dash display for a truck that was free 'cuz of electrical issues.
Now that we have a taste of the good stuff, can't wait to see this through from the 'surprised when it works'
to the 'surprised when it doesn't work' level of reliability.

You are getting close to the goal...

 

[Additivewalnut]

Q: Have you had a chance yet to try to add those grounds like you proposed back in reply #38? (LINK)

Your latest observations about the dash suddenly working is a very positive indication -- lots of stuff
is able to work, but only when all that stuff doesn't have to try to work through a marginal ground path.
And with all the vibrations of a truck being driven down the highway, it makes sense that some of that
vibration may have (temporarily) helped to jostle a bit better electrical path in a nearly broken connection.

It really seems that there is an intermittent issue in factory splice S207, which your proposed additional
individual ground wires to the IP and dimmer circuit will either fix outright OR further our troubleshooting.

Dude, that's a heckuva nice looking nighttime dash display for a truck that was free 'cuz of electrical issues.
Now that we have a taste of the good stuff, can't wait to see this through from the 'surprised when it works'
to the 'surprised when it doesn't work' level of reliability.

You are getting close to the goal...

Very close indeed! I added a ground to the dimmer, but couldn't seem to get a good spot on the IP, the way the harness is tucked behind the dash makes it almost impossible... but seeing this kinda helps me justify the work.

 

[Erik the Awful]

You know the taillight wiring is bad. That's low-hanging fruit. Fix it first.

 

[Road Trip]

You know the taillight wiring is bad. That's low-hanging fruit. Fix it first.

^^^^ Like Erik said. A lot of times fixing the obvious will also clear up the exotic symptoms too.

Here's an example from elsewhere in the forum where the trailer connector/wiring adversely affected
the IP display in a counterintuitive way. It's a short thread, and pay attention to @GrimsterGMC 's
post #7 at the end: (Weird IP behavior traced to trailer connector)

 

[Additivewalnut]

^^^^ Like Erik said. A lot of times fixing the obvious will also clear up the exotic symptoms too.

Here's an example from elsewhere in the forum where the trailer connector/wiring adversely affected
the IP display in a counterintuitive way. It's a short thread, and pay attention to @GrimsterGMC 's
post #7 at the end: (Weird IP behavior traced to trailer connector)

Huh. That sounds way too easy to work in my case. The way my wiring was put in looks like a blind man did it, I'm gonna full on cut it out and see if I suddenly have a dash again.

 

[Erik the Awful]

My son's parking lights came on whenever the battery was connected, and the turn signals didn't work. I repaired a broken ground wire near the rear bumper and it fixed everything. Don't underestimate it. If nothing else, it's distracting you from doing solid work. It needs fixed so instead of standing there, scratching your head about the issue, tackle what you know is wrong.