Having read about a few others on here lately who have had some battery issues, I am passing along something I found tonight on my truck.

At times I have experienced a weak battery and the sight gauge on my battery often shows red. My trucks battery will drop down to ~9 volts when it cranks and then back up to 13+ volts after it is running.

I was looking to upgrade my "Big Three" this evening and happened to run across a grounding problem on my truck. What I found was one of the ground wires from the fender to the wiring harness was not tight against the fender. The bolt was very tight, but I could move the cable in and out on the bolt. Below is a picture of the location I am talking about on the passenger side fender. The cable in question is the one on the right and the picture is from after I installed an additional ground cable to the location as a part of my upgrade.



I am hoping this will make a difference going forward as I clearly was not making a solid ground on this wire to the body.

 

No pic?

 

That grounding wire won't be the root cause of your battery failure. Either you have a bad battery or you have a charging issue (or a parasitic power drain when the truck is off).

 

Sorry about that, I had renamed my gallery and lost the link, it's fixed now.


It may well be a bad battery, but a bad ground could also cause a charging issue.

The bolt was very tight like it was bottomed out against the fender, I am guessing others may have a similar issue.

 

Unless the cable you tightened was like a #4 or so in diameter, it wouldn't be part of the charging system.

 

That is the main grounding point for the PCM. If the PCM has an intermittent ground it will never fall asleep and continue to drain your battery. All our trucks when shut off and locked up will pull ~0.5A for about 10 minutes and then the PCM will command all the truck modules to shut-off. If any of those modules including the PCM have a power reset, the whole truck wakes up again. An intermittent ground will act like a power reset.

The wire to the left of the picture is the main chassis grounding point to the battery. You essentially now have two runs from the chassis wall to the battery. If the PCM has a poor ground connection, it can play games with the charging system since it commands voltage. However, if the PCM command and alternator control voltage are not the same you will pull a "Check Charging System" message or telltale light on the dash. - and the alternator at worse case will run in default which is at the minimum of 13.5v.

 

Deere... do you ever leave you key in the ignition for a long period of time? I did once and it killed my battery. So much infact, that even the Ford dealers charger after a 3hr charge read 0A after disconnected.

I think I will check my ground too just for the heck of it now though too.

 

I haven't left my key in for extended periods without the truck running. I first noticed that when I remote started my truck it quit starting, just the lights would come on. Later I experienced that it would take up to a minute for the A/C to come on even though it was 90+ outside.

I may have a bad battery as well, but I am going to keep an eye on it now that I have tightened it up.

 

I guess the problem is, with the key in the ignition the truck will not sleep. Little things that stay active while the key is in are things like the active seat adjuster and radio. My dealer told me the new trucks arent like the old ones where you can leave the key in the ignition

 

Well I have a 2009 F-150 FX4, I have had to have the battery replaced twice in less than a year. The dealership says the batteries were just dead, no kidding right? Thats all they will give me for an answer. I find this problem to be unexceptable. Has anyone else had these types of problems? Possible solutions?

 

Im having the exact same problem with my 09 right now as well. Only difference is Im not having the weak battery issue.

 

I have to a F150 FX4 and I have had to have the battery replaced three times in last year. The dealership says this was defect on this year supplies of batteries.

 

BS ... You have a parasitic battery drain.

Common (though not limited to), known causes of battery drain ...

• LEAVING THE KEY IN THE IGNITION. *TAKE IT OUT BEFORE LEAVING THE VEHICLE.
• leaving devices plugged-into the electrial recepticles. *They're ALWAYS hot.
• central timer module (component of BMS) turning on by itself intermittently. *Part of the Body Control Module.
• back-up camera harness short. - http://www.fordraptorforum.com/f7/mo...harness-41847/
• faulty ignition switch. (key loose in)
• faulty shift lever micro-switch. - http://www.f150forum.com/f38/dashboa...2/#post3825056
• faulty door -closed- switch.
• faulty hood -closed- switch.
• BMS was not recalibrated after applying the ssm4475 - http://www.f150forum.com/f38/radio-d...0/#post3951468
• software calibration issue with the BMS. http://www.f150forum.com/f38/radio-d...0/#post3962167
• the sync option causing a draw/dead battery. *First check for codes in the APIM. TSB 9-14-3
• central timer module turning on by itself intermittently. *Part of the Body Control Module.
• bad ignition switch. - http://www.f150forum.com/f38/dead-ba...4/#post3997086
• BCM REPROGRAM for SSM 44750. *Changes the low voltage threshold.
• the mirror cover on the passenger visor does not close causing the light to stay on - http://www.f150forum.com/f38/battery...1/#post4160675
• Ford had a recall on 2011 f150's for bcm failures. NHTSA 10V659000
• ... IPC reprogram which had fixed some trucks and they have also resoldered instrument cluster solder joints and replaced clusters to fix others. - http://www.f150forum.com/f2/another-...3/#post4328042
• bad instrument cluster - http://www.f150forum.com/f38/need-he...9/#post4331565
• three wiring harnesses, one of which has been mentioned here, the C405 connection. I believe this is the rear camera, tail light harness. - http://www.f150forum.com/f38/need-he...9/#post4355870
• CHMSL pinched wire - http://www.f150forum.com/f38/battery...9/#post4435255

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