Truck Battery Runs Down When Parked

[CougarXR7]

I replaced both alternator and battery after about the third time this happened. When one gets weak, it takes the other out unless you catch it early in failure.

I would agree with this. Having owned nothing but Fords since I was 16, I have seen this happen more than once. If one component goes bad, it could possibly take the other down with it. Also, older Fords can have charging issues if they don't have strong battery connections and good, clean grounds. Make sure you have clean and tight terminals on the battery posts. Ensure that the heavier gauge cables don't have "green rot," and check the grounds between the frame and engine block.

They really are great trucks. I have the Mazda variant, but it is essentially a Ranger. :nerd:

 

[KingBubba]

I have a problem like this with my 2003 Chevy Suburban. A Google search showed that there was an extended issue with battery draw down. The great majority of issues had to do with the onboard computer and the need for a recall software update, which apparently my truck did not get, or was outside of the recall. According to the service manager at the local dealership. a typical draw, after a 3 hour rest following shutdown, should be in the neighborhood of 25 milliamps between the battery post and the cable. Anything more indicates a problem elsewhere. Using your amp setting on your meter, check each fuse position looking for draw. Pull the fuse and insert the meters probes in both sides of the fuse holder. It's worth a try.

I still have not gotten around to doing this on my truck, but soon I'll get to it. Good luck.

 

[Redikilowatt]

I'm on my second Ranger. First was a 1999 and current is 2003. Had several electrical issues with the '99 and a cascading set of events that had me replacing battery, alternator, and relay on the 2003. Love the truck, but electrical problems are standard equipment on the Ranger

Like you, Tox, I go days or weeks without needing the truck so batteries don't last long.

Here's mine

 

[quaddriver]

btw - on ford truck alts from 87-on, 83 on car alts, if you replace the alt, you MUST replace the cable - it comes in the box....

 

[petehall347]

if you was to remove the battery and overnight charge it then check voltage .it should be about 13v if good .
then check it again 24 hrs later it shouldn't drop much .maybe 12.6v . this however isn't same a voltage drop test .. easy to do really . just disable engine from starting if you can figure that out then connect volt meter to battery and crank engine for 20 seconds .if volts drop below 10v on a charged battery its time for a new battery .
more and more i am finding vehicles that will flatten batteries if left for a few days .its the alarm systems that are doing it . i generally disconnect the battery if being left more than 2 days . not recommended for security though .

 

[sKiZo]

Here's my other one ...

Always liked the type one bodies ...

 

[BobbyBluz]

I did 35+ years as an auto service tech. The standard method for finding battery draws is to disconnect the positive battery cable then put a 12 volt test light in series between the terminal & post. As others have posted start pulling fuses one at a time until the light goes out. Whatever is on that circuit will be your culprit.

 

[petehall347]

i saw a fuse the other day in a car that was lit up .. i thought hang on what's going one here .asked the owner .he said its got an led inside all the rage these days . am wondering if these could be fitted as an instant display of parasitic power draw or not ?

 

[Cantilope]

My truck is parked for days and days, I use a battery tender on it. It's the only way and keeps the battery healthy. Parasitic draw is pretty common, my Harley does it too. However the CJ5 can be parked for a year and fire right up every time.

Try a tender. I got my last one on Amazon. They have long cables and a quick plug. I actually keep my plug in the bed of the truck just under the rail where it's closest to the plug. All my non-daily drivers have one.