Random loss of all electrical power

[provin1327]

Hey guys, I'm running into a strange issue with my 2006 Ranger 4.0L auto 4x4. Last year I replaced the battery since it needed replacing. Easy swap, all went well. However, about a week later I was driving the truck out of the driveway and all of a sudden I lost all electrical power. Everything shut off and went dead for a second. Then all my dash lights and gauges turned back on, I turned the key and the truck fired up no problem. A few weeks later it happened again. Instant loss of all electrical power, truck dies for a second then everything kicks back on again and starts right up. My first guess was something with the battery since I had just replaced it but I got to thinking that if the truck is already running then a bad connection at the battery terminal or bad battery wouldn't cause it to loose all power and die. I decided to clean all of the relays and fuses and make sure they're all set in their slots correctly. That seemed to fix the problem until today when it happened again. This time the truck died for about 10 seconds and I had no power. I tried to crank it over and nothing, no gauges, no radio. Then all of a sudden everything turned back on and the truck fired up. What could be causing this? Based on how intermittent and short it is I feel like I should be looking for some sort of bad connection or loose wire but I'm not exactly sure where to look or what else it could be. Any ideas? Could it actually have been the battery? Seems highly unlikely since it's only happened a handful of times.

 

[RonD]

Welcome to TRS

The Battery is ONLY used for starting the engine, after startup the Alternator provides ALL the "power" for the vehicle
Batteries are 12.3 to 12.8volts
Alternators output 13.5 to 14.8volts
So voltage runs TO the battery when engine is running, nothing comes FROM the battery, and this keeps battery charged for the next time you need to start engine

Your problem is most likely a bad Negative terminal on the battery, or bad negative cable or connection, so follow those cables to where they connect to body, and engine and clean them

Next could be where Positive cable and alternator's cable connect to fuse box
Follow the smaller of the two positive battery cables to the engine fuse box
There should be another red wire there as well that's from the alternator
These two wires connect at the same place on the fuse box
This connection provides ALL the 12volt power, from battery and alternator to the vehicle thru that fuse box

So either a bad Ground(negative) or a bad Positive wire, and thats it, the only places that could cut all electrical power

 

[provin1327]

Thanks for the reply RonD. Electrical systems are not my specialty. I was able to clean the positive and negative posts on the battery (not really that much corrosion but a little bit), where the wires connect to the positive and negative terminals, the negative ground to the body, and the two wires connecting to the fuse box. Everything looked fine but I scrubbed them anyways and applied some Super Lube Anti Corrosion Gel to all connections.

I was not able to clean the negative ground to the engine (too much snow on the ground) but I was able to get my fingers on it from above and it's tight. It seems so strange that the problem is intermittent and it's difficult to diagnose or track it down since I cant replicate it on demand. For now hopefully cleaning those connections works.

 

[RonD]

It should, the only place that can cut alternator and battery 12-14volts both is the connection at the fuse box, or the main engine ground

If just engine died but dash lights stayed on then could be PCM relay
You can also check the larger fuses in engine fuse box, the 40-60amp fuses
They feed the cab fuse box and ignition switch, so if one lost power it would be like shutting off the key, but long shot on that
Pull them out and look for corrosion

And that takes you to the ignition switch itself, there is just ONE wire that feeds voltage to ignition switch(under steering column)
In 2006 its from fuse #9, 40amp, in engine fuse box
If that wire loses power its the same as turning key OFF

 

[provin1327]

Thanks RonD I will keep those other options in mind if the problem continues.

 

[provin1327]

The problem still exists but now things have....changed.

I just started the truck up fine but just like the first time this problem arose the truck died as I was pulling out of the driveway only this time the PATS icon is lit up on the dash. If I put my foot on the brake the PATS icon goes away but the truck wont start. If I take the key out and my foot off the brake the PATS icon is illuminated solid. Nothing works, no lights, no radio, no accessories, nothing. I tried my spare key and it does not work, does the same thing PATS icon just illuminated solid. How can I reset this stupid PATS system? I think that may be what's killing all power to the vehicle.

After waiting 10 minutes I tried to start the truck again still nothing and the PATS system blinked 4 times, pause, then it just blinks and blinks like it's trying to give some sort of fault code but it just keeps blinking. I can hear a relay clicking in the fuse box that coincides with the blinking. I tried to turn the headlights on and I can hear a relay clicking rapidly I removed the key and I can hear and see a very faint blinking of the PATS light but it's not flashing.

 

[RonD]

There is no "relay" for PATS, its a transistor on/off in the cluster on 2004 and up

You have an HEC instrument cluster, in a 2006, a micro-processor controlled cluster

Google: HEC cluster dealer test mode

You can sometimes get Trouble codes(DTCs), these are Body or Chassis codes so start with B and C, not P

These include PATS codes

As seen here: http://www.carlogic.org/bg/data/Ford HEC dealer mode.pdf

Note this
DTC = Displays continuous DTC's in hexadecimal format. Pressing the SELECT/RESET button will display any DTCs stored before proceeding to the next step.
Have pencil and paper, write them down, or click, click, click with camera

 

[provin1327]

I cant get it into HEC dealer mode. It does nothing.

I have no idea what the hell is clicking but something is and it's so weird that when I try to turn the lights on it also clicks whatever relay is down there. My only option on this one might be to have it towed to the dealer Luckliy I was not left stranded by this fucking bullshit PATS system and this fault happened in my driveway.

 

[RonD]

You may need to get Ford to do a diagnostic on the cluster, if you can't get it into test mode then there IS a problem, and PATS is IN the cluster

The cluster is "matched" to the engine computer(PCM), so you can't just swap it out, Ford needs to "re-match" a new cluster

 

[Orca]

I cant get it into HEC dealer mode. It does nothing.

Over time, I've seen more people with 2004+ Rangers who say the HEC test mode does not work than those who say it does!

Here's a relevant thread showing 2 people with a 2006 Ranger who cannot get it to work (and 2 who say it did work, but both appear to have a 2009 Ranger).

It's never worked on my 2004 Ranger. I tried to get others with 2004 or newer Rangers to try this simple test but got no responses.

And here's another guy with a 2004 that says it doesn't work.

FORScan has an IC (Instrument Cluster) "On Demand Self-Test" that works on my 2004 Ranger. Might be worth a shot if you can run the Windows version of FORScan.

 

[provin1327]

Well the dealer found the problem. Turns out the battery was faulty and was putting out low voltage causing the PATS system to go haywire. The first few times the truck died and lost all power it showed symptoms of a bad ground/connection at the engine or fuse box but in reality it must have been the PATS system killing the vehicle just for a split second.

I knew I should have trusted my gut and replaced the battery since this all started just a few weeks after I replaced the battery but it just did make any sense as to a bad battery causing the problems I was seeing. I'm lucky the dealer was only able to bend me over for $300 on a new battery and cables.

 

[RonD]

Glad you solved the problem

Yes.........."new" used to mean "tested and working"
Now-a-days new means "you test it and we will warranty it"

If you ever wondered why Motorcraft parts are so stupid expensive its because they are tested before being shipped from manufacturer, Car companies can't afford to put in untested parts into new cars
It can still happen, i.e. "recalls" but just less likely to happen

So if its a hard to get to part, like a fuel pump, I would get Motorcraft, if its easy to get to 3rd party all the way, save the money, lol