Battery Light ON
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Battery Light ON
new to me 2014 F-350 6.7L SD CC dually Lariat with ~119,000kms. Bought last summer but parked for the winter. Ran great last summer/fall. Started up after several months off and battery light comes on after about 25secs. Put voltmeter on each battery - reads about 26 motor off; about 23 running with AC max, radio, flashers, etc (hope I'm reading that right...). What might be the problem? New alternator about $600CDN + labour so hope that's not it... wiring seems ok from what I can see. Also did check after disconnecting battery for about 24 hours....
TIA
PS - not terribly mechanically inclined old guy here....haha
TIA
PS - not terribly mechanically inclined old guy here....haha
Postmaster
Joined: Nov 2015
Posts: 4,807
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From: Colorado Springs
new to me 2014 F-350 6.7L SD CC dually Lariat with ~119,000kms. Bought last summer but parked for the winter. Ran great last summer/fall. Started up after several months off and battery light comes on after about 25secs. Put voltmeter on each battery - reads about 26 motor off; about 23 running with AC max, radio, flashers, etc (hope I'm reading that right...). What might be the problem? New alternator about $600CDN + labour so hope that's not it... wiring seems ok from what I can see. Also did check after disconnecting battery for about 24 hours....
TIA
PS - not terribly mechanically inclined old guy here....haha
TIA
PS - not terribly mechanically inclined old guy here....haha
Typically the light comes on when the batteries are below a preset voltage. Did you charge the batteries BEFORE starting it this Spring? The alternator is not designed to charge batteries. You don't mention how old the batteries are? Take them out and have them load tested by someone that knows what they doing. In the future put a trickle charger on the batteries if you're going to let the truck sit, or bring them inside and charge them but ALWAYS put the charger on them if the truck sat for a long time.
Any chance you checked the Batteries BEFORE you tried starting the truck?
Posting Guru
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new to me 2014 F-350 6.7L SD CC dually Lariat with ~119,000kms. Bought last summer but parked for the winter. Ran great last summer/fall. Started up after several months off and battery light comes on after about 25secs. Put voltmeter on each battery - reads about 26 motor off; about 23 running with AC max, radio, flashers, etc (hope I'm reading that right...). What might be the problem? New alternator about $600CDN + labour so hope that's not it... wiring seems ok from what I can see. Also did check after disconnecting battery for about 24 hours....
TIA
PS - not terribly mechanically inclined old guy here....haha
TIA
PS - not terribly mechanically inclined old guy here....haha
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Thanx for the reply - so dual batteries not in series? duh (have to tell my "mechanically inclined" neighbour haha)... Multimeter set to DCV (needle type, not digital) and set to 50 scale (options are 10, 50, 250, 500)... Nope - did not charge before this spring as truck started ok; not sure battery age... and did not check batteries this spring before starting it, only after battery light came on....
Maybe time to get a different multimeter....
Maybe time to get a different multimeter....
Logistics Pro
Joined: Nov 2004
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Many posts in these forums about new alternators being put in that turn out to be bad.
If you have dual batteries, one bad one could be causing the problems.
Would be worth it to take it somewhere to have both batteries load tested and the new alternator tested to as these are the simple solutions.
If you have dual batteries, one bad one could be causing the problems.
Would be worth it to take it somewhere to have both batteries load tested and the new alternator tested to as these are the simple solutions.
Fleet Mechanic
Joined: Oct 2017
Posts: 1,704
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From: Southwest Ohio
I know an Autozone manager and he has tested (on the fancy store tester) known bad batteries that test as good. He has also tested new refurb units which tested good but were bad (battery light stays on, swaps alternator for another and problem resolved). Those auto parts alternators are crap, as it’s a gamble if you’ll get a good one.
— Dave
— Dave
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UPDATE - Battery Light ON
Ok - so my analog multimeter was screwed! I bought a digital meter: both batteries were about 12.1 so charged each up to 14.8; next day each at 12.6 w/o load; with load drops to 11.7/11.8 and the battery light came back on - conclusion: damn alternator??? (PS - nothing on the analog matched the digital so something busted inside - threw away....)
TIA
TIA
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Logistics Pro
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Ok - so my analog multimeter was screwed! I bought a digital meter: both batteries were about 12.1 so charged each up to 14.8; next day each at 12.6 w/o load; with load drops to 11.7/11.8 and the battery light came back on - conclusion: damn alternator??? (PS - nothing on the analog matched the digital so something busted inside - threw away....)
TIA
TIA
when you says it drops under load to 11.7, do mean with the engine running? If so, then yes - something’s wrong on the alternator side. Check the belt and wiring. If they look ok and are tight, then have the alternator tested.
Postmaster
Joined: Nov 2015
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From: Colorado Springs
Ok - so my analog multimeter was screwed! I bought a digital meter: both batteries were about 12.1 so charged each up to 14.8; next day each at 12.6 w/o load; with load drops to 11.7/11.8 and the battery light came back on - conclusion: damn alternator??? (PS - nothing on the analog matched the digital so something busted inside - threw away....)
TIA
TIA
I figured something was whack with your meter.
Lead Driver
Joined: Dec 2006
Posts: 7,092
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From: San Diego, CA
If you do not want to get your batteries tested I would do one more check before chalking it up to the alternator. Start the truck and let it idle for a few minutes (guarantees the glow plugs are off). Disconnect both batteries (carefull with the cables as they are "hot") and check to see if your battery light is on. Take a VDC reading at the alternator or on one set of battery cables. You should see 14+ VDC.
The only times my battery light has come on was for alternator issues but I verified my batteries were good as the first step each time. One bad battery can drag down your alternator. Just my .02
The only times my battery light has come on was for alternator issues but I verified my batteries were good as the first step each time. One bad battery can drag down your alternator. Just my .02
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