Voltage drops when running lots of accessories
Thread Starter
|
Junior User
Joined: May 2016
Posts: 86
Likes: 1
Voltage drops when running lots of accessories
89 F150 lariat xlt here. I recently fixed the ac/heat and I've noticed at night if I have the headlights on, the ac, and maybe a blinker or windshield wipers or whatever the voltage will drop significantly and the truck will even die at a red light or whatever unless I give it some gas. I'm thinking maybe I need a better battery but I thought I would throw it out to the hive mind and maybe there's another reason for the voltage drop. Thanks ya'll.
Logistics Pro
Joined: Nov 2004
Posts: 4,795
Likes: 47
Check the battery voltage - should be 12.5 or 12.6 off. If it is, the battery should be good.
Then turn the engine on and test the battery agsin when it’s running. Should be at least 14. If it’s under that, your alternator might not be working right.
Then turn the engine on and test the battery agsin when it’s running. Should be at least 14. If it’s under that, your alternator might not be working right.
Fleet Owner
Joined: Oct 2005
Posts: 20,786
Likes: 1,751
From: Kentucky
Keep in mind the factory 2G alternator puts out very little to no power at idle/low RPMs. That's a design flaw. Highly suggest you upgrade to a 3G to fix your current issue and prevent the flamethrower 2G from claiming another victim.
Thread Starter
|
Junior User
Joined: May 2016
Posts: 86
Likes: 1
So I just checked the battery with a voltmeter and I got 12.6 and when I start the truck I've got 14+ so I don't think it's the battery. Must be the 2G alternator. I'm looking on Napa's website now and I don't see them labeled as 2g or 3g so I'll give them a call and figure it out. Thanks ya'll.
Napa alternators
Napa alternators
Fleet Owner
Joined: Oct 2005
Posts: 20,786
Likes: 1,751
From: Kentucky
The factory replacement alternators listed for your truck are all 2G design. Everything you wanted to know about the 3G upgrade: https://www.fullsizebronco.com/forum...ins-agian.html
Thread Starter
|
Junior User
Joined: May 2016
Posts: 86
Likes: 1
The factory replacement alternators listed for your truck are all 2G design. Everything you wanted to know about the 3G upgrade: https://www.fullsizebronco.com/forum...ins-agian.html
Thread Starter
|
Junior User
Joined: May 2016
Posts: 86
Likes: 1
Trending Topics
Fleet Owner
Joined: Oct 2005
Posts: 20,786
Likes: 1,751
From: Kentucky
Order an alternator for one of these:
(1994-95) Ford Mustang 5.0L
(1994-00) Ford Mustang 3.8L
(1994-97) Ford Thunderbird, Mercury Cougar 3.8L
(1990-95) Ford Taurus, Mercury Sable 3.8L
(1993-99) Ford Taurus, Mercury Sable 3.0L
(1995-98) Ford Windstar 3.8L & 3.0L
(1991-94) Lincoln Continental 3.8L
(1994-95) Ford Mustang 5.0L
(1994-00) Ford Mustang 3.8L
(1994-97) Ford Thunderbird, Mercury Cougar 3.8L
(1990-95) Ford Taurus, Mercury Sable 3.8L
(1993-99) Ford Taurus, Mercury Sable 3.0L
(1995-98) Ford Windstar 3.8L & 3.0L
(1991-94) Lincoln Continental 3.8L
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
Laughing Gas
Joined: Feb 2015
Posts: 765
Likes: 1
Do the 3G upgrade, totally worth it. Installed a 95 mustang v6 alternator rated at 130 amps. You gotta use an angle grinder to cut the bracket slightly to make it fit and fabricate wiring but it's not that bad. I was very impressed with the results.
Laughing Gas
Joined: Aug 2010
Posts: 983
Likes: 49
From: Northern Kentucky
I did exactly as above and all works great.
