Those really fun electrical problems
Thread Starter
|
New User
Joined: Aug 2017
Posts: 6
Likes: 0
Those really fun electrical problems
Hey guys, I know this is everyone's favorite subject but I'm at a loss. I moved my 66 f100 out into the street to wash it the other day and when I went to move it back there was no power to the starter. After further testing I saw that there was no key on power to the solenoid. Also I put a multimeter on the battery which has 12.6 volts until the key is switched on and to goes down to about 2. I replaced the ignition switch today, and now nothing electronic works. The battery still has about 12.4 volts and things that get direct battery power are still lighting up the test light but that is as far as it goes. I hope I can get some feedback but its hard to explain through text what is going on. If you have any questions I will do my best to explain further and I greatly appreciate any feedback! 
Fleet Mechanic
Joined: Aug 2016
Posts: 1,480
Likes: 6
From: Great White North
Well that is a big voltage drop. Start by pulling all the fuses. Next install one fuse at a time and see which accessory gives you a drop when you turn the key on. Once you find it repair or replace the device and/ or faulty wiring.
Mountain Pass
Joined: Jul 2017
Posts: 169
Likes: 5
From: Ahwatukee
Does the voltage taken right on the battery drop to 2 volts when you turn he key on (put it under load), or does the battery actually stay near 12 volts while the voltage drops to 2 somewhere else in the circuit?
If battery itself drops that low, then you probably have a bad battery, try another one if you can. If it's the circuit that is dropping that low, then it's probably a bad ground somewhere and RangerMercMan has given you good advice on how to proceed.
oh, and don't forget to check the battery connections for corrosion.
If battery itself drops that low, then you probably have a bad battery, try another one if you can. If it's the circuit that is dropping that low, then it's probably a bad ground somewhere and RangerMercMan has given you good advice on how to proceed.
oh, and don't forget to check the battery connections for corrosion.
Thread Starter
|
New User
Joined: Aug 2017
Posts: 6
Likes: 0
Does the voltage taken right on the battery drop to 2 volts when you turn he key on (put it under load), or does the battery actually stay near 12 volts while the voltage drops to 2 somewhere else in the circuit?
If battery itself drops that low, then you probably have a bad battery, try another one if you can. If it's the circuit that is dropping that low, then it's probably a bad ground somewhere and RangerMercMan has given you good advice on how to proceed.
oh, and don't forget to check the battery connections for corrosion.
If battery itself drops that low, then you probably have a bad battery, try another one if you can. If it's the circuit that is dropping that low, then it's probably a bad ground somewhere and RangerMercMan has given you good advice on how to proceed.
oh, and don't forget to check the battery connections for corrosion.
Post Fiend
Joined: Feb 2008
Posts: 5,831
Likes: 121
From: St Albert, Alberta
that is another weird part. I didn't use a multimeter but I put a test light on the battery post with the key on and it lit up bright (I'm assuming the full 12.4 volts) then, if I touch it to the other end of the positive cable (on the starter solenoid) it is very dim. Then of course if I turn the key off, the light brightens back up.
That cable is NFG or the connections are dirty. Try cleaning the connections both ends. If that does not fix it replace the cable.
Post Fiend
Joined: Feb 2008
Posts: 5,831
Likes: 121
From: St Albert, Alberta
Trending Topics
Thread Starter
|
New User
Joined: Aug 2017
Posts: 6
Likes: 0
There is 12 volts to everywhere until the key is turned on. I have a multimeter on the battery which is showing 12.4 volts and the headlights will not come on. Nothing will work.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
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
Ford Super Duty: 5 Things Owners LOVE, 5 Things They LOATHE!
Joe Kucinski
Every 2026 Ford Truck Engine RANKED from WORST to FIRST!
Michael S. Palmer
The Best F-150 Deal of Every Trim Level (XL through Raptor)
Joe Kucinski
Thread Starter
|
New User
Joined: Aug 2017
Posts: 6
Likes: 0
Ok, a little update. With a multimeter attached to the battery cables at the terminals. I turned on the headlights and voltage dropped to less than 1 volt. I turned on everything that doesnt require key on power and it all dropped the battery voltage. Ive never had this happen but all the cables look ok on the outside, could it really be a bad cable?
Fleet Mechanic
Joined: Aug 2016
Posts: 1,480
Likes: 6
From: Great White North
that is another weird part. I didn't use a multimeter but I put a test light on the battery post with the key on and it lit up bright (I'm assuming the full 12.4 volts) then, if I touch it to the other end of the positive cable (on the starter solenoid) it is very dim. Then of course if I turn the key off, the light brightens back up.
That kind of changes everything. I assumed you were using a voltmeter. The starter solenoid is dropping your voltage as it should. You have a bad connection in the starter circuit or your solenoid is simply not engaging and it needs replacing.
Actually I just reread your post and it sounds like your positive cable needs cleaning and tightening or replacing.
Thread Starter
|
New User
Joined: Aug 2017
Posts: 6
Likes: 0
That kind of changes everything. I assumed you were using a voltmeter. The starter solenoid is dropping your voltage as it should. You have a bad connection in the starter circuit or your solenoid is simply not engaging and it needs replacing.
Actually I just reread your post and it sounds like your positive cable needs cleaning and tightening or replacing.
Actually I just reread your post and it sounds like your positive cable needs cleaning and tightening or replacing.
Fleet Mechanic
Joined: Aug 2016
Posts: 1,480
Likes: 6
From: Great White North
Ok, a little update. With a multimeter attached to the battery cables at the terminals. I turned on the headlights and voltage dropped to less than 1 volt. I turned on everything that doesnt require key on power and it all dropped the battery voltage. Ive never had this happen but all the cables look ok on the outside, could it really be a bad cable?
I guess you posted this before I got my reply in before. Your battery sounds hooped. There is a tool known as a V.A.T. 40 (and similar tools) where V= voltage, A= amperes and T= time. When the tool is hooked up and turned on it puts a "load" on the battery for a period of about 15 seconds. The voltage should not drop below 12 V during this test or your battery is hooped. Have you tried a jump start or push starting if you have a manual transmission? An auto parts store might be able to test your battery for free. Battery cables are cheaper than a battery but if you do replace them get the largest cable size (smaller awg # is a bigger wire) as it will greatly improve your electricity flow.
Thread Starter
|
New User
Joined: Aug 2017
Posts: 6
Likes: 0
I have to admit I have never had battery or cable issues like this. I had checked everything else so I was like "well it can't hurt" the cables werent too coroded but I cleaned them anyways and it worked! I feel dumb for not doing that first but I'm glad shes back up and running. Thank you for all of the help and suggestions!