What am I doing wrong? ACCESSORY MODE

[RagmopInKona]

https://www.mustang6g.com/forums/threads/bms-reset-no-tools-required.151602/

Thanks, I admittedly suck at searching for things on this forum. I must use the wrong wording .

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[Sabre]

Have both your battery tested and your alternator output tested. Most of the auto parts stores can easily do this for you. It could be that your battery is continually low because your alternator is not keeping it fully charged.

 

[ORRadtech]

Have both your battery tested and your alternator output tested. Most of the auto parts stores can easily do this for you. It could be that your battery is continually low because your alternator is not keeping it fully charged.

Having both tested isn't a bad idea. But e said it only gets driven once a week for short trips. That's not really enough for an alternator to recharge what's used. That kind of use is almost a death sentence for a battery.

 

[Sabre]

Having both tested isn't a bad idea. But e said it only gets driven once a week for short trips. That's not really enough for an alternator to recharge what's used. That kind of use is almost a death sentence for a battery.

You're right of course. But it's possible it's a combination of both.....a good maintainer is obviously the best answer here.

 

[Johnny Rockit]

The car is only 2 yrs old. 8K miles.... How do you test a battery (other than with a multimeter)? In other words, how can I test it to make sure it is functioning properly?

I bought a harbor freight load tester a couple of years ago. Maybe $20 but worked well on my wife's Toyota. It is worth the money in my mind. I bought a nice chrome snappy unit decades ago that had less technology than the HF.

 

[fmc_smt]

Unfortunately a load tester is only so good . The modules look at battery state of charge .

 

[Johnny Rockit]

Unfortunately a load tester is only so good . The modules look at battery state of charge .

My battery was replaced before I picked up my car. It had to be jumped for the test drive. The app had a couple of codes showing. It pays to use a good battery tender. While you are infinitely more knowledgeable than I will ever be, the tester doesn't hurt anything that I know of. I am going to be immersing myself in the forum once I put a few miles on my ride.

 

[Garfy]

I have had my 2020 mustang GT for 2 years and haven’t changed how I operate the car…. But….

lately it seems the accessory mode is staying on even after I power off car. This causes the car to turn over slowly when I turn it back on a little while later AND more annoying, it loses my gauge and sometime the seat settings (I have digital dash).

WTF am I don’t wrong? I take foot off brake and press button. I get out of car. Sometimes I lock it.

I haven’t modified anything either.

do I need to take it for this? Anyone else have this problem?

I have the same year GT as you except mine is the regular analog type dash, not digital (base model GT). However, I only have 4000 miles on mine (bought in Nov 2020) but I put a charger on it from time to time if it sits more than a week without driving. My battery tests above the rated CCA using these small capacitance type testers (they don't actually "load test" the batteries like in the old days, but they are fairly accurate in assessing the condition of the battery).

As far as your accessory mode, on mine, once I open the door everything shuts down (except the exterior park lights that stay on for maybe 20-30 seconds then shuts off). If I don't open the door, the radio turns off in 10 minutes whereupon I have to push the radio power button to turn it back on again then it stays on for 20-30 minutes (I forgot how long it was but certainly longer than the default 10 minutes when turning off the engine.)

I would have Ford check out your system to make sure it's shutting down properly when you exit and lock the doors. As mentioned above, you could have a marginal battery as well.

 

[KingKona]

The car is only 2 yrs old. 8K miles.... How do you test a battery (other than with a multimeter)? In other words, how can I test it to make sure it is functioning properly?

So the battery is really 3-4 years old, and it's been ruined by sitting without being charged.

Yes, it's time to replace it.

 

[Grettman]

I am lucky to have access to a Ford Dealership "Mobile" service unit. They came to my home free of charge and tested the battery and it was fine (tested with car off and when it was cranked). Determination was made that I need to drive it more --- that the battery wasn't fully charged during my short drives. Apparently, the car gives the engine priority when starting which may cause the electronics not to have enough power if the battery wasn't sufficiently charged. I will wait and see how things go. I will get a battery tender and/or drive it more. Thanks everyone.

 

[Likeit]

https://www.mustang6g.com/forums/threads/bms-reset-no-tools-required.151602/

I keep my car's on a battery charger because they are not driven daily and after 7yrs on one off the car the battery is still strong at 14_Volts.

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