Not Your Typical Battery Drain Issue

[BrianF1973]

I am new to the site, and am happy to be here.

Here is my problem (its a doosie). This is a little long winded, so please bear with me.
I bought a 2005 Sport Trac Adrenalin in September 2017. I drove it daily for the first 30 days to see if there were any bugs to address. For the most part, everything was OK. Then the problems started. Since this is an extra vehicle, it sits in the street for days at a time. I would go out and have to jump start the truck after as little as 48 hours. I was told to get a new battery since the one in there was from Walmart. So, I went and bought an Interstate battery and had the same issue. Being an Electronics Technician and understanding such things, I attempted to find the source of the drain myself. I even completely unplugged the aftermarket stereo since that was the most obvious culprit. This was all unsuccessful and frustrating. I then took the truck to an Auto Electric place that was highly recommended. They told me they couldn't find an abnormal drain but found the driver door latch assembly was broken and could be randomly waking up the truck. $250 later, I drove it home only to have a dead battery a week later. I took it back to the Auto Electric place and they kept it for a week and found no abnormal drain, but did say the battery was suspect. Since I had just bought the battery 6 months prior, I took it back for a new one under warranty. Two days later, I had to jump start the truck again. The next day, it was dead again. This time I took it to the Ford Dealership. They told me that the alternator was not charging properly. $650 later, I picked it up. I had to go out of town, and after letting it sit for 4 days, my wife checked it and the battery read 8.5 volts. She had it towed back to the Ford Dealer to check it out again. They kept it for a week and found no abnormal drain. Here is where things get a little crazy.
The technician at Ford told me that he has seen security cameras interfere with vehicle PCM and wake up the vehicle. My neighbor has a NEST camera pointing out the front of his house, so the tech told me to try parking it out of range and see what happens. I skeptically agreed and took the truck home. I am now waiting to see what happens.
I did some research online and it appears that EMI from things like cell phones, garage door openers, etc can effect PCMs. What I can't seem to find is if there is any way to prevent it. Do I need a new PCM? Can I shield it and still use the keyless entry?

To summarize, battery is dead in as little as 48 hours. New Battery, New Alternator, New Driver Door Latch Assembly. Any time the vehicle is not at my house, there is no battery drain. Crazy Technician thinks neighbor's Nest Camera is the reason.

If you read this all the way through, thank you for your time.

 

[MAS Tequila]

Faraday Cage

 

[sr139fox]

Cover the suspect area in copper screen and ground to chassis. This might prevent the wireless signal from getting through. Also check grounds on the system. A missing ground might cause it. You need to send the wireless signal to ground.

 

[koda2000]

Does you BATT/CHG light work? Sometimes a bad diode in the alternator or problem with the voltage regulator can suck the charge out of a battery when the engine isn't running. Remove the alternator and take it to an auto parts store to get it tested.

 

[mic98xlt]

Very interesting situation. On the Sport Trac firewall there is grounding strap that goes from the firewall to the engine block. The metal stud that the grounding strap is attached to is painted "green" and is right next to the PCM itself and provides the ground for the PCM plus the entire metal firewall. I would make sure the ground strap is there and on the correct green stud. When my mechanic changed the engine on my 2003 Sport, he accidentally replaced the ground strap on the wrong stud. It's very easy to assume the ground is good (valid) while being placed on the wrong stud, which caused weird problems such as my fan blower not working.

 

[1998Exploder]

First off, get yourself a Ford wiring diagram book from eBay. Should be about $20.

Next, time for some troubleshooting. Real troubleshooting. Pop the fuse panel on both cabin and engine bay. Take pics and note fuse values. Your manual will also help. Remove every fuse from both panels and let the truck sit for 2-3 days. If your battery is strong, the leak is not in the charging circuits.

Next, if pre distribution block and loss of voltage, the drain is somewhere in the charging circuits. This is by far the easier problem to fix because there are fewer wires and components (e.g. battery, alternator, etc)

If the drain doesn't happen, reinsert all engine distribution block fuses without inserting cabin fuses, charge battery with second vehicle and wait again. If distribution block OK, move to the cabin block and reinsert all the fuses. You can start to pinpoint the culprit using a multimeter for each of the fused circuits in the cabin panel. Or simply start adding fuses one at a time and monitoring voltage over time.

This takes time, but ultimately you can find the leak simply by handling fuses. Again, a multimeter can help speed this up tremendously once you narrow down the general drain area.

Good luck.

 

[firefly1246]

I have personally had a similar issue which after 3 months of intense diagnosis ended up being a bad starter on a Ford Escape. Approx 75% of the time when you stopped somewhere it would drain the battery until it was dead. During that time it killed 2 batteries and I replaced alternator which didn't change anything.

To determine if you are having a similar issue to what I had with the starter you could park it and disconnect the wires to the starter. Which is fairly easy to get to under the truck. Make sure you start by disconnecting the battery, then disconnect the starter wires, cover up the starter wires to ensure they don't short, then plug the battery back up. And come back in a few days to see if the battery is still good.

Another option is to purchase a multimeter with a clamp to detect D.C. Current. Just make sure it does D.C., cause the cheaper ones only do AC current. I purchased one on Amazon for $45. With the car parked you can see how much drain you have coming from the battery. Then go to different wires and see how much current they are pulling.

My personal opinion is the PCM is not the issue as the draw is super low on it. It is designed to literally be on all the time, like the clock. You have something draining with some significant draw on the battery.

Good luck!

-Scott

 

[BrianF1973]

Not much to report, but I thought I would post an update. Of course the EMI theory from the dealership was a Red Herring. I have started using the ST as a daily driver just so I don't kill the new battery that is in it. My ammeter checks lead me into the guage cluster, but I am hesitant to put a new one in. If it isnt the problem, then I spent a lot of money and effort for no reason. It is possible that the problem I have with my gas gauge would be fixed, but even that is a gamble. I have noticed that there is a high pitched wine comming from the speakers when the truck is off. So there is EMI comming from something into the speaker circuit. However, I disconnected everything associated with the radio and still had a drain.

 

[koda2000]

What I would do until you figure out the real problem is to purchase a battery switch so that you can easily disconnect the battery when the vehicle is not in use and reconnect it when your driving it. There are inexpensive ones at the auto parts stores or you can spend more and get a fancier more expensive security style one on-line. That way you can at least use the vehicle w/out having to jump-start it every two days.

You've spent a freaking ton of money on this issue trying to get other's to find/fix it. It hasn't worked. You're going to have to find it yourself. I'd be taking Ford stealership to court to get my $650 back. They did nothing for you and shouldn't get paid for it! My money is on the charging or starting circuit. Maybe you have a relay that's stuck in the ON position.

I for one do not want to hear that you've paid anyone another penny to find this problem. You've already added almost a $1000 to the purchase price of that vehicle for nothing. Diagnosing electric problems takes time, but you don't have to pay for your time. Think about the problem logically and test the circuits until you find the one that's hot when it shouldn't be.