Problems with Dark Horse going Dead

[hayw01]

My 2024 DH mustang goes dead if I don’t start it every 2 days, I have had a brand new battery installed and it still does it. We keep a trickle charger on it and it seems to work but we bought it brand new off the lot in May 2025. This doesn’t seem right, does anyone else have this problem

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[robvas]

Parasitic draw or something. Have the dealer take a look at it. When they can't figure it out find a good stereo/electronics shop that can diagnose it.

 

[smurfslayer]

Record the car overnight inside the cab and outside; see if the car is waking up uncommanded. I have seen of a bad sync module causing this.

Is the car stock?

 

[Dxm]

it could be car alarm that was not properly installed, or something like that. It's not normal. On a stock car, the battery should be good for at least a month. Maybe you have something plugged into the cig lighter/USB that drains the battery? A dash cam could do it, although on the Mustang the power gets shut off after an hour. Maybe worth checking.

 

[135Hoser]

if it’s stock take it to the dealer.

In what world would this be normal or expected behaviour.

 

[Neggytive]

either a crap battery, of which there seems to be more than a few people who have had them replaced under warranty, or a parasitic draw.

Either way back to the dealer for them to load test the battery and or check for current draw after the BCM goes to sleep

The sleep mode draw should be under 25 milliamps IIRC, if you had a amp meter you could go in series with the negative cable and measure it, but load testing the battery would be where I started

 

[glenng6]

My 2024 DH mustang goes dead if I don’t start it every 2 days, I have had a brand new battery installed and it still does it. We keep a trickle charger on it and it seems to work but we bought it brand new off the lot in May 2025. This doesn’t seem right, does anyone else have this problem

I once had a similar problem that was a mercury switch, for the under hood light, that would stay on when the hood was closed. But I doubt that the Mustang is using any Mercury switches. I had a 1970 Ford Torino Brougham and if I didn't start it every two hours, the car wouldn't start. Talk about a pain in the ass! It was more than likely an open circuit somewhere, but Ford couldn't sort it out, and a new battery didn't work! So I traded it in! Problem solved. I certainly hope you have better luck! Glenn

 

[Zig]

Ours is not a dark horse but an early ‘24

By chance did you get this alert in fordpass?

 

[BimmerDriver]

I once had a similar problem that was a mercury switch, for the under hood light, that would stay on when the hood was closed. But I doubt that the Mustang is using any Mercury switches. I had a 1970 Ford Torino Brougham and if I didn't start it every two hours, the car wouldn't start. Talk about a pain in the ass! It was more than likely an open circuit somewhere, but Ford couldn't sort it out, and a new battery didn't work! So I traded it in! Problem solved. I certainly hope you have better luck! Glenn

Back in the day before trickle charger and proximity remotes and other tech, we'd just install a battery cutoff to resolve these kind of issues. Of course, that was also in the day when (like the Torino) you could open the hood from outside the car, not that we had electric locks anyway.

Ah, the good old days. Points and condensors, leaded fuel, no computers, 8 MPG. LOL

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