2001 F150 XLT 4x4 Supercrew 5.4L Triton V8

WTF Happened:I plugged a power inverter (input DC12v, output AC110v 200w) into the cigarette lighter/power plugin (can't remember which) to run my laptop. This worked for about 10 minutes then didn't.

Symptoms:
When I open the door, the hazards and high beam lights on the instrument cluster flash. The lights themselves do not come on.

Insert key, turn to on, all lights in cluster come on as normal, but if I open the door the hazards/high beam lights on the cluster come on and flash off-on about every 5 seconds. Close the door, a few seconds later they go off.

Engine starts normal. No power windows, no AC/blower. Cannot tell if lights are on, but when I turn them on the hazards/high beam indicator lights come on again. High beam light indicator turns off when I turn the high beams on. The actual headlights/hazard lights do not come on though.

However, set to Max AC, engine off, key removed, I can feel the blower on low. After a few seconds the hazards/high beam light came on in the cluster. Opening the door did not shut the blower off.

Drove it to four places. From A-to-B drove normal, but didn't test whether the windows worked. Point B is where I tried the test procedure I mention below. From points B-to-C and C-to-D it started making that buzzing sound you hear in the video.


Action Taken:
• Checked every fuse. They all appear okay.
• Tried the instrument cluster test procedure (hold down reset button on instrument cluster, turn key to ON position). I can't find anywhere it says when to release the button, so I tried it 3 times, releasing it at different points. The odometer would say test then make a weird buzz every 5-10 seconds. I don't know what the indicator is that shows the test is complete or what is supposed to say when it finds something.
• Unhooked negative battery terminal for 10+ minutes.
• Unhooked both terminals for 10+ minutes.
​​​​• Prayed.

I'm stranded in Dallas, halfway between where I'm coming from (KC) and where I'm going to (Brazoria County) unless I can figure this out and MacGuyver something together. I got a well used Haynes manual and the tools to pretty much disassemble and reassemble the whole damn truck. I just need some direction.

 

New development: I have a Bluetooth obd reader. I just hooked the battery back up after having the negative terminal disconnected for the past hour. Figured I'd it started up normal, then1 run it through the engine idle relearn.It didn't help. I have a Bluetooth obd code reader, so I thought I'd check again for any codes. Plugged it in (while running), everything appears to be working normally. Lights came on, blower works, window rolled up, locks....working as usual.
Had it running while typing this. Just started smelling smoke, then saw a couple whisps floating up. Something under the dash was burning. Pulled the reader and the charger I was using to charge my phone. As soon as I did, the original issue started up again. And the reader melted a bit around the back where it plugs in.

I'm guessing there's a short somewhere and plugging in the reader completed a circuit, powering everything on?
I replaced the #3 fuse (OBD reader) and the #6 (cluster). Still having the issue.
​​​​​

 

Here is the melted OBD reader. Number 4 pin is charred.

 

You've got a complex shorted wiring problem. Kinda doubt if anyone can help on that through a forum discussion. Possibly mouse chewed wires ??

Trying to find a short can be tedious and difficult. Start by inspecting all visible wiring under the dash and see if there are obviously damaged wires. Either damaged by rodents or fraying or heat.

For everything to suddenly stop working could mean a bad ground.

 

I doubt that...

That's what I'd first suspect. Pin 4 of the OBDII plug is supposed to be chassis ground. I'd suspect that, when the OBDII dongle was attached, it temporarily completed an open ground path temporarily, at least until the magic smoke got released. Pin 5 is the signal ground. Chassis and signal ground are supposed to be connected together at G101 which is under the hood, on the firewall, passenger side. That's the very first thing I'd check due to the OBDII dongle melting.

After that, pull the kick panels, starting on the passenger side, and inspect the grounds for loose connections, corrosion, and body rot.

If you've been in rain, be suspicious of water ingress at the windshield corners. Water ingress into the electrical systems, especially the GEM and fusebox, can cause all kinds of mischief.

 

Took it to a dealership to test the battery because, according to the online consensus, "Fords do weird s*** when the battery is bad."
They say the battery is good.
Went to O'Reilly's to have them plug in their code reader.
Couldn't communicate with the OBD. The kid had to start the truck just to get it to pick up on his reader, and as soon as he plugged it in, the driver's window went down (and stayed down). It rolled up fine as long as he was plugged in, so we timed it to where he'd wait to unplug it after I rolled it up.

​​​​​I just read your responses. I'll find a QuikTrip somewhere in an area that looks less likely I'll get jacked and start looking at grounds and damaged wires.

​​​​

 

It's not #4, it's #5 that burned out.
Wait, first, did take off, clean, and reinstall the 5 grounds I could find going to the firewall. I know there are more, everything electronic is dying until I can find a place to charge them.

Anyway, #5 is the Signal Ground circuit 570, which I'm going to become an expert in shortly. I followed the OBD wires into the steering shaft...and that's where I'm at.
I had another theory though:




The connector is toast, so, thinking that I must have had the reader plugged in when I plugged in the AC adapter power inverter, and since they're on the same fuse the sudden pull might have went to the reader too but was too much and shorted/melted the plug there forcing the wires to touch, I pulled out both of the wires and wrapped them separately
​​​​​​ in electrical tape.
This attempt met with negative results. Though the constant blink is different and it's not freaking out as much when I try to use an accessory. Everything is still jacked up, just jacked up a little less?

 

Is there some reason you didn't have them check for the source of the problem ?

 

Sorry, I implied but did not specifically state this in my initial post: My budget the project is $0.

A bad battery could have explained the symptoms. I bought it in March at a dealership, so it's under full warranty, and warrantied batteries have to have the printout from the tester when they're sent back so the dealership gets credited for it, so I knew it'd either confirm or rule it out via a diagnostic test.

The feeling I got was the shop leaned more towards being "glorified parts exchangers" than "mechanics."

This was confirmed when the service advisor came back with the test results. He was sincere and everything, but his (and the tech's) was for the tech to "spend a few hours disassembling the PCM and see if there was a problem there." Didn't mention diagnostics, testing circuits, etc.
I'm sure they'd eventually get me back on the road, but even if I had the money I'd probably have passed and spent the last 24 hours hunting down a real mechanic.

 

Ask yourself how a bad Battery burns anything up?
Excessive over current on a lead will burn things!. That's not from a faulty Battery.
Good luck.

 

I'd suggest completing the list of things I gave you yesterday morning and see how that turns out. Report specific results.

Unless you really like running around in circles....

 

Maybe it's just the way I word things, but:

"I just read your responses. I'll find a QuikTrip somewhere in an area that looks less likely I'll get jacked and start looking at grounds and damaged wires."

I quoted myself there to show that I acknowledged your response and was going to do just that.

I underlined part of it to point out a contextual clue that may have alluded to the fact that my situation may not have allowed me to go from A to B without needing to pause for something else.

Me posting things that I found during the course of the investigation doesn't mean I blew you off.

"Wait, first, I did take off, clean, and reinstall the 5 grounds I could find going to the firewall. I know there are more, everything electronic is dying until I can find a place to charge them."

Here I noted I was in the process of completing the task but was facing another complication. I felt it prudent to report and further findings before I lost comms.

The symptoms could also be explained by a bad battery. Given this was something covered by warranty, it meant needing to go to a dealership, which the hours of operation meant during that timeframe I needed to prioritize getting it done. Which I did, ruled it out, and while I was able to charge my phone a bit at the dealer, I didn't have a way to charge it so I reported my findings and left to find a spot to continue looking for grounds and tracing wires back.

Looking for a spot to park and continue the task in Dallas, where it's still in the 90's, during business hours, where I could be in the shade and out of sight-out of mind, meaning I'm not interrupting any business, not being a target for theft, and not attracting unwanted attention from Karens, cops or tow truck drivers.

Maybe I'm alone here, but in the past few years on 4 occasions I had a vehicle that broke down and was towed, despite me parking out of the way, had only left to get a tool or part, was away from anywhere between 2 - 12 hours, and, in one case, actually had permission from an assistant manager. That time it took me 5 days to come up with the ransom tow fee. They were going to scrap my car on day 6. I have since become very selective about where and when I work on vehicles while away home, which can take a bit of time.

When I was finally able to find a spot, I continued with the task of checking grounds, the findings of which are in the following post.

 

SOLVED

I need to point out I might have been wrong in something I reported above. While the #5 wire (signal ground) was melted and appeared to be the culprit, a test with a multimeter showed it was fine. The #4 wire (chassis ground) was actually the one shorting.

#5 ground point could have also need bad, idk. I tested it at the OBD port after I had cleaned the ground point (under the hood, on the firewall, as you're facing the vehicle it's the 2nd or 3rd ground point from the left) so I may have corrected the issue.I made my way around the truck, hitting all the ground points.

As another user proposed, it was behind the passenger side kick panel. Pulled it apart, cleaned it, put it back together and used dialelectric grease, everything came back to life.

To wrap up, and to help with the search function: The #4 OBD2 wire (chassis ground) in the 97-03 generation F150 connects to the ground point located behind the passenger side kick panel. If you're having an issue with accessories not working and suspect a short to ground, check the passenger side kick panel ground point.

Even if it looks fine, take out the bolt, clean the connection, use dielectric grease, and reinstall.

 

To clarify, you did not have a "short" to ground. A "short" is an unintended path for current to take. You had the opposite - an open or high resistance that did not allow the ground circuit to do what it was supposed to by its intended paths.

Glad you found and fixed it.