Dead Battery
Thread Starter
|
Junior User
Joined: Jul 2006
Posts: 97
Likes: 0
Dead Battery
I have a 78 f100 302 auto my battery keeps going dead once a week or so, this just started happening a few weeks ago. Its got new startet, voltage regulator, solenoid and alternator I even went and bought a new battery and the same thing happens does anyone have anyother ideas?
Posting Guru
Joined: Jul 2003
Posts: 2,222
Likes: 1
From: East Central Florida
When the truck is off with the key off, do you show a current drain above 7 or 8 milliamps?
do you have an accessory engine lamp?
Does your brake lamp Switch open the circuit completely every time?
Do all your interior lamp door switches work correctly?
Do your 4 way Hazard Flashers work properly?
Do all your accessories shut down with your Key Off ?
FBp
do you have an accessory engine lamp?
Does your brake lamp Switch open the circuit completely every time?
Do all your interior lamp door switches work correctly?
Do your 4 way Hazard Flashers work properly?
Do all your accessories shut down with your Key Off ?
FBp
Last edited by FordBoypete; Aug 15, 2006 at 10:55 PM.
New User
Joined: Jan 2008
Posts: 0
Likes: 24
Freshman User
Joined: Aug 2006
Posts: 33
Likes: 0
Use your volt meter if you have one and see if the is a draw coming off the battery from ground to battery ground. if so there is a battery cut off switch you can buy at any auto parts store that will fix the problem. If there is a power draw trying to find it is really time consuming and a real pain.
Senior User
Joined: Sep 2003
Posts: 141
Likes: 1
I little back yard mechanicing is all you need. Here is what you do if you do not have a voltage regulator.
You will need a fully charged battery. Disconnect the neg battery terminal. If there is a short somewhere in the truck when you touch the neg terminal back to the neg post on the battery it will spark (engine / key off).
Now comes the detective work. Remove one fuse out of the fuse block at a time. After you remove one fuse check to see if the battery terminal when touched to the neg post is still sparking. Once you find the one that stops the sparking you know where to start. There is a short somewhere between the fuse block and accesory. You can then go straight to the accesory (for example the radio) and disconnect it and reinsert the fuse into the fuse block and check for sparking. If no sparking occurs with the accesorry disconnected chances are the accesory is bad.
If you remove all the fuses and still nothing try disconnecting the voltage reg, relay to starter connection, alternator, etc. Remember to check for spark after each thing you disconnect.
You should be able to locate the short in under an hour
You will need a fully charged battery. Disconnect the neg battery terminal. If there is a short somewhere in the truck when you touch the neg terminal back to the neg post on the battery it will spark (engine / key off).
Now comes the detective work. Remove one fuse out of the fuse block at a time. After you remove one fuse check to see if the battery terminal when touched to the neg post is still sparking. Once you find the one that stops the sparking you know where to start. There is a short somewhere between the fuse block and accesory. You can then go straight to the accesory (for example the radio) and disconnect it and reinsert the fuse into the fuse block and check for sparking. If no sparking occurs with the accesorry disconnected chances are the accesory is bad.
If you remove all the fuses and still nothing try disconnecting the voltage reg, relay to starter connection, alternator, etc. Remember to check for spark after each thing you disconnect.
You should be able to locate the short in under an hour
Trending Topics
New User
Joined: Jan 2008
Posts: 0
Likes: 24
It seems 2 posts of mine never made it to this thread.
I tried posting a link to the page that describes the "How to find a short".
Hmmmm... I wonder why my posts didn't come through ?
I tried posting a link to the page that describes the "How to find a short".
Hmmmm... I wonder why my posts didn't come through ?
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
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
Postmaster
Joined: Apr 2000
Posts: 2,838
Likes: 6
From: SD
Sixty-five is right, but I would recommend using a test light instead of the spark tecnique - if you don't have a test light, buy a good one it's a good investment and you will use it lots in the future. Disconnect the neg battery cable and connect the test light on the neg cable and the neg battery terminal, if there is a draw the light will be lit. Keep in mind that having the doors open (turning on the dome light) will make the test light be lit. So pull a fuse and close the doors to see if the light goes out. The most common problem areas are dome lights, vanity mirror lights, radio, alt and brake lights. Let us know what you find.
Marty
Marty