Community Forums

EGRJR · 02-11-2025, 02:11 PM

Hello Class A Owners:

I own a 2020 Forest River FR3 DS30 motorhome – uses a Ford F-53 chassis of course. Have any of you experienced your red battery light indicator at the dash coming on when you are driving while using several of your accessories i.e. wipers, AC or heater with fan, radio, fog lamps? The red-light indicator will come on for about 4 minutes then it goes off for a while, then will come on again. I’ve never had any issues that have left me stranded. Under the Ford warranty, alternator has been replaced twice along with 2 different chassis batteries – didn’t resolve the issue. Those technical experts out there, here are the voltage readings from the chassis battery with a voltmeter.

Engine off – 12.46v
Engine on – 14.57v
Engine on using 5 accessories – 14.53v

The red light is coming on for a reason besides driving me crazy trying to figure it out. Any thoughts/ideas for resolution? Thank you for your assistance.

twinboat · 02-11-2025, 04:02 PM

This may be out in left field but some F53s had a wiring harness getting burnt down by the drivers side, where it comes close to the exhaust pipe, causing issues. Worth a look.

EGRJR · 02-12-2025, 03:56 AM

At this point I'll check anything. Thanks for the suggestion.

SandiaMan · 02-12-2025, 09:10 AM

Sure does not look like it is an alternator issue with your posted voltages, although with engine off battery at 12.4V is lower than a fully charged battery would read. With your posted alternator voltages your chassis battery should be nicely charged after a bit of driving, with engine off and your coach plugged into shore power what are your chassis and house battery voltages?

d23haynes57 · 02-12-2025, 09:15 AM

Alternator may be getting overloaded overheating charging the house batteries. Is the voltage still high when the light is on?

SafariBen · 02-12-2025, 10:10 AM

You don't have any solar do you? An alternator warning light is not always an indication of alternator trouble, especially if the voltage is still good, or there are other power sources like a generator or solar, possibly even a Li charger and house to chassis tie at the same time or alternately.

Randalpho · 02-12-2025, 10:58 AM

I replaced my daughters battery in her 2015 Ford Escape and the battery light was on after starting it. Ford states after replacing a battery to reset the Battery Management System, they have a Battery Sensor attached to the negative battery cable that monitors volts/amps.

This worked to reset it and it's supposed to work on all/most Fords. You could give this a try, it might come back on if there is a true issue.

Turn on the vehicle ignition using the key or push-button start
Flash the brights five times
Press the brake pedal three times
Wait for the battery light to flash

twinboat · 02-12-2025, 11:33 AM

Quote:

Originally Posted by Randalpho

I replaced my daughters battery in her 2015 Ford Escape and the battery light was on after starting it. Ford states after replacing a battery to reset the Battery Management System, they have a Battery Sensor attached to the negative battery cable that monitors volts/amps.

This worked to reset it and it's supposed to work on all/most Fords. You could give this a try, it might come back on if there is a true issue.

Turn on the vehicle ignition using the key or push-button start
Flash the brights five times
Press the brake pedal three times
Wait for the battery light to flash

An F53 is a different class of vehicle and doesn't have a battery management system like an Escape.

EGRJR · 02-13-2025, 05:28 AM

When the red battery indicator light is on the battery reads 14.53v.

EGRJR · 02-13-2025, 05:31 AM

The MH has a solar connection available but I don't use it. My MH is stored at my residence and I have a 50amp connection to maintain the 2 house batteries when necessary.

EGRJR · 02-13-2025, 11:38 AM

SandiMan - I went out this morning and took the MOHO for a drive and returned home and checked the battery voltage and it read 12.6v

Gary RVRoamer · 02-13-2025, 12:03 PM

I may be obsolete regarding this, but back in the day the red "idiot light" measured the flow of amps in/out of the chassis battery. As long as the alternator was pushing amps towards the battery, the light was green or (more often) off. If amps were flowing out of the battery (thus feeding the chassis 12v needs), the light was red. The voltage doesn't tell you much for sure about the light, though voltage above 13.0 is a good sign.

twinboat · 02-13-2025, 12:44 PM

Nowdays, the light is indicating voltage from the alternator.

No light = alternator voltage higher then battery voltage.
Red light = battery voltage higher then alternator voltage. Not a specific voltage but just higher.