What wires have constant power?

[1984ranger28]

Hi, my Ranger is having a problem with a parasitic draw. I was wondering how many wires are always live and where I could find them. I have a 1984 with the 2.8l. Thanks, Lucas.

 

[RonD]

Shouldn't be much in 1984

The positive battery cable runs to the Starter Relay(solenoid) on the inner fender, that post it is connected to is the 12v Power Distribution for the whole vehicle
So all the other wires on that post send 12v out to systems full time, alternator is also connected there

Head light switch
Dome and glove box lights, hood light if there is one

Radio KAM(keep alive memory), it holds radio pre-sets and clock time.

Ignition switch has power full time on one side

Brake pedal switch.

You can use a test light to check battery flow, or volt/amp meter
Key off
Disconnect either battery cable, ground is best, then hook 12volt test light between cable end and it's battery terminal, it should light up a bit if there is just a small draw, brighter it is the bigger the draw.

Then start unplugging fuses, in engine fuse box first, test light will get dimmer if power was flowing thru that fuse.
And/or unhook the wires on the starter relay post


Also just a heads up, Batteries can be self draining, they get an internal short between two plates and slowing drain power.
And this can "act like" a parasitic draw, i.e. battery charges fine and starts engine fine after 1 to 5 hours, but overnight, 8+ hours, it won't start engine, battery is too low

With either battery cable disconnected put a volt meter on battery and watch voltage, should stay stable, leave it for a few minutes then check again, if voltage is going down battery has an internal short, for sure.
Seen this on older batteries mostly but did have one new battery that had a short inside

The plates inside the battery are very close together and any debris inside can cause the short, and as a battery gets older there is a build up on the plates from charging and discharging that can "grow" and touch, which causes the short.

 

[adsm08]

The plates inside the battery are very close together and any debris inside can cause the short, and as a battery gets older there is a build up on the plates from charging and discharging that can "grow" and touch, which causes the short.

Not to mention that as the battery gets some years on it the chemical reaction and the road vibrations can degrade the plates and cause pieces of them to fall out, sometimes bridging two plates.

On an 84 I would be willing to be a true parasitic draw is either in the radio system, or the alternator.

If it dies in just a few hours look at the alternator. Short of a vehicle with an amp installed most draws from the radio take at least a day and a half to kill the battery.

 

[1984ranger28]

Thanks. I already did the fuse trick, there is still voltage going to the battery (Cant measure amps because my voltmeter broke and cant read amperage anymore). The battery is only 2 years old. It usually has only 12.20 volts but never fully dies.

 

[Curious Hound]

, there is still voltage going to the battery .

What do you mean by this? The battery supplies the voltage. I'm not trying to be a jerk. Just want to understand your statement so we can try to help you further. If you follow RonD's procedure, you should be able to narrow this down to the problem circuit. Make sure everything is turned off and the doors are closed when you do it.

This message composed solely of recycled electrons. Go green!

 

[Ranger850]

2yr old battery doesn't mean much. the cheaper batteries usually are warrantied for a year, so anything after that is just luck. Check to see if you have a wal-market special. Batteries fail by design, because they need you to keep buying them.

 

[adsm08]

Thanks. I already did the fuse trick, there is still voltage going to the battery

That is like saying "I removed the straw, but the juice box still has juice in it."

(Cant measure amps because my voltmeter broke and cant read amperage anymore).

You probably have a blown fuse in your meter.

The battery is only 2 years old. It usually has only 12.20 volts but never fully dies.

Take it to a parts store and get it tested. Volts does not equal amps.

Volts is the pressure to push amps along the wire. Amps are what are actually doing the work.

 

[RonD]

Two year old battery should show 12.5volts, new battery is 12.8v to 13.0v

5/6year old battery is 12.3volts

12.2v is a dying battery

So I would do as adsm08 suggested, have it tested.

Or if you have a friend to help............
Unplug the Coils spark wire, you want a No Start
Put volt meter on battery and get a reading
Then with volt meter still on battery crank over the engine for 10 seconds
Watch battery voltage, should drop to 9.8v but no lower over the 10 seconds, most will stay above 10volts

Generally you would see a 2volt drop, maybe 2.5v, with a good battery, more than that means battery doesn't have enough CCA(cold cranking amps) left.
So its either not being charged enough by alternator or battery is no longer able to store/hold a charge


The other very simple test is to unhook one battery cable when you get home and leave it off
Then hook it back up the next day and try to start engine
If it starts up OK then you have a parasitic drain
If it cranks slow or not at all then battery is at fault

 

[1984ranger28]

What I meant by "voltage is still going to the battery" is that im taking the ground wire off of the battery, taking the two leads from the voltmeter, and putting one of the leads on the negative post on the battery, and the other on the ground wire. Ill try getting the battery tested. Thanks.