Help finding an electrical leak
Thread Starter
|
Freshman User
Joined: Aug 2011
Posts: 47
Likes: 0
From: statesboro
Help finding an electrical leak
I recently replaced my battery and alternator. They both check out fine, but when I park my truck at night sometimes my battery is down to 8 or 10 volts when I go to start it in the morning. I can jumpstart the truck and it will run just fine, which leads me to believe I have a drain in my electrical system somewhere. Any ideas on where I should start looking?
Lead Driver
Joined: Jul 2009
Posts: 6,477
Likes: 19
From: Sheffield, AL
An alternator [even new or rebuilt] with a bad diode can act as a short and drain a battery.
Take one of the terminals off the battery and using a 12 volt test light, connect to the battery and loosened cable. If the light is bright, then electricity is flowing due to something pulling current. At this point, you can start removing fuses one at a time until the light goes out. That will indicate which circuit is involved and then you can go from there.
Are you sure your interior light is not on? Have you recently installed a new sound system with amplifier?
Take one of the terminals off the battery and using a 12 volt test light, connect to the battery and loosened cable. If the light is bright, then electricity is flowing due to something pulling current. At this point, you can start removing fuses one at a time until the light goes out. That will indicate which circuit is involved and then you can go from there.
Are you sure your interior light is not on? Have you recently installed a new sound system with amplifier?
Cargo Master
Joined: Apr 2010
Posts: 2,936
Likes: 9
From: Acworth, GA
I recently replaced my battery and alternator. They both check out fine, but when I park my truck at night sometimes my battery is down to 8 or 10 volts when I go to start it in the morning. I can jumpstart the truck and it will run just fine, which leads me to believe I have a drain in my electrical system somewhere. Any ideas on where I should start looking?
Here are a couple of things that might help you out.
Here is where they are located if you need anything else; https://www.ford-trucks.com/forums/m...it.-page2.html
pedant
Joined: Jan 2008
Posts: 23,576
Likes: 38
From: EXTREME southwest CT
Dollars to doughnuts the 2G alternator plug of your 1986 F150 is shorted internally.
Did you replace the pigtail when you replaced the alternator as outlined in Ford's Technical Service Bulletin 96214?
Did you replace the pigtail when you replaced the alternator as outlined in Ford's Technical Service Bulletin 96214?
Trending Topics
Thread Starter
|
Freshman User
Joined: Aug 2011
Posts: 47
Likes: 0
From: statesboro
No I did not change out the pigtail I will check on getting a new one first thing in the morning
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
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
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Post Fiend
Joined: Jul 2004
Posts: 8,786
Likes: 28
From: Northern California
If everything checks out using pulling the fuses, the plug at the alternator is fine etc... and you still have a draw, the external voltage regulator (if equipped) or altenator are suspect.
A bad diode in the external voltage regulator, (if equipped) can also drain the battery.
A bad diode in the external voltage regulator, (if equipped) can also drain the battery.
Senior User
Joined: Feb 2012
Posts: 177
Likes: 0
From: Grants Pass, OR
Another possibility is a bad ignition switch.
A bad switch can leave some items powered on that shouldn't be. For example the computer. Note that not all items run through the fuse box. Some items are powered through fuse links only.
A bad switch can leave some items powered on that shouldn't be. For example the computer. Note that not all items run through the fuse box. Some items are powered through fuse links only.
Thread Starter
|
Freshman User
Joined: Aug 2011
Posts: 47
Likes: 0
From: statesboro
I charged the battery overnight and placed it back in the truck. I ran the test light between the negative battery terminal and the ground wire and did not get any light from it even after ten minutes.
Thread
Thread Starter
Forum
Replies
Last Post