What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Electrical problems

I

itsnachotime

Registered Member
Joined
Oct 2, 2022
Posts
8
Reaction score
0
Location
Colorado springs
Hi everyone ! I'm new to the CK5 community and a new owner of an 86 K5. So I have had the truck for about a month and one problem keeps plaguing me. The battery drains incredibly fast and eventually the truck sputters and dies. I notice it when I have my normal headlights on. ( I pull the light switch on and the truck sputters and lunges until I turn it off. I jumped the truck but the batter is too dead for that to work. I recharged it at O'Reillys but eventually it dies. I went through the grounds cleaned and scrubbed but I'm back at square one. I think it has something to do with the headlights, but electrical is my weakest subject. Any ideas how I should diagnose electrical issues? Thank you in advance!. - rob
 
Welcome to CK5!
Do the headlights look bright or somewhat dim? Based on the information I would guess your alternator is not outputting voltage. When the truck is started you should be able to measure around 14V at the battery terminals. If you are just running on battery it will drain down and die, especially with the headlights as they pull a bit of power. If the alternator is working, it should have more than enough output to run everything.
O'Reillys should be able to check to see if the alternator/charging system/batt is good.

Good luck
 
Thank you for your input. The headlights are super dim almost not worth turning on honestly. I will start with the alternator. Thanks again !
 
Get your self a volt meter / multi meter, quick searches on you tube for finding draws / drains on electrical systems, or get a manual from an auto parts store.

You can disconnect your negative battery cable set the multi meter to 10 amps dc and use the multi meter probes, one on the negative terminal and the other on the battery cable and it will tell you if you have a draw. Then you can remove a fuse at a time to find what circuit the draw is in.

Sounds like you need to start with your headlight circuit. Probably a wiring issue, look for broken or pinched wires, taped up messes in the wiring. But with a little learning on the use of a volt meter you can diagnose where the issue is pretty quickly.

Welcome aboard and I know we have a few members in the springs and nearby that might chime in. You will be far ahead by learning how to diagnose and locate the issue rather than throw parts at a problem on a guess.

I also don't like wiring but I am getting better at it, spent several hours yesterday and today diagnosing a charging issue on the wife's truck and eliminating bad wiring due to the alternator not charging.
 
Thank you for the instructions on how to find a draw. I'll invest in a multimeter and research techniques on diagnosing my issues. Thanks again, I'll have her up and running soon.
 
I'm going second the alternator not charging.
First with engine off, measure voltage at your battery. A fully charged battery is 12.6v. if you are below 10v with truck off charge battery.
With engine running and everything electrical turn off you want to see 13.6v to 14.2. above 13 but below 13.6 at idle is acceptable if the voltage increases with engine rpm.
Now if you have 13.6v or better, turn head lights and heater blower hi, raise the rpm to about 2000 and see the voltage output, it should better than 12.6v. 13.6 is ideal. If you get 15v or higher that is no good.
Make sure your negative battery cable has a good solid connection at the engine block, not a bracket or exhaust manifold. You need a negative, ground wire, to the radiator core support, and the truck frame.

Welcome to CK5. Please let us know what you find. These steps are beginning and we can help get more in depth as needed
 
If you dont have an external Volt meter to test the Voltages at the battery you should be able to tell by looking at your Alternator Voltage/Batt gauge in the cab to see what it reads when the engine is off and running. If it moves up around 13/14V when running, alternator is probably good, if it stay rock steady around 12V or less and does not move with slight increases in RPM, then its probably bad.

As much as I hate to say it, if in fact the alternator is bad and you have been draining the battery down to where it wont start, you will probably want to look at replacing the battery soon. That kind of repetitive drain/strain on most battery's will damage them and greatly shorten their life.

If you are not aware (I have no knowledge of your auto mechanical/electrical background), the battery is only there to start the vehicle and/or provide temporary power to the vehicle when engine is not running. When engine is running, the alternator takes over and provides all the power to run everything including charging the battery back up. You can technically run the vehicle without the battery once its started if the alternator is good.
 
Wes Harden said:
I'm going second the alternator not charging.
First with engine off, measure voltage at your battery. A fully charged battery is 12.6v. if you are below 10v with truck off charge battery.
With engine running and everything electrical turn off you want to see 13.6v to 14.2. above 13 but below 13.6 at idle is acceptable if the voltage increases with engine rpm.
Now if you have 13.6v or better, turn head lights and heater blower hi, raise the rpm to about 2000 and see the voltage output, it should better than 12.6v. 13.6 is ideal. If you get 15v or higher that is no good.
Make sure your negative battery cable has a good solid connection at the engine block, not a bracket or exhaust manifold. You need a negative, ground wire, to the radiator core support, and the truck frame.

Welcome to CK5. Please let us know what you find. These steps are beginning and we can help get more in depth as needed
Click to expand...
With the truck off I am reading normal. At idle with electrical off I am at 12.42 not sure if that is acceptable.
 
I tis not, next carefully check the big red wire on back of alternator with engine running. If not better voltage then the alt is probably no good.
Shut truck of and find the terminal before you try the measurement. It is not difficult but there is a lot to keep in mind the fan, belts, and shorting your meter to ground while checking
 
Yep sounds like bad alternator. So take it off have it tested and replaced, if you have the old one with you no core charge. Also if you have a battery charger charge the battery up so the new alternator doesn't have to
 
You want to use the volt meter to check voltage at Big red wire at back of alt. That wire is always hot, had voltage,. It should should same voltage as battery with truck off, and higher voltage running.
 
When I say volt meter I mean digital volt meter, a tool. I do not mean the dash meter
 
You must log in or register to reply here.

Latest Posts

Top Bottom