Hi Folks...

I'm having an electrical problem with my 1988 Ranger.

The battery is draining out on a nightly basis.

It's a 2-liter with 2WD and minimal options.

I took it to an alternator shop and the guy showed me how to do a continuity check with the positive battery cable, which my truck failed. (he said my alternator was fine)

What do I do from here? I've had this truck just over a year and this seems like a new problem.

I've replaced the battery, the negative (red) cable and recently replaced the starter.

Do these trucks have a typical fault or common problem to help me cut down time searching for what's shorting or draining my battery?

 

got an ammeter?

If so, with the truck turned off, disconnect the ground cable.
Then, install the ammeter in SERIES with the battery and the disconnected ground cable. Check the amperage draw.

By finding the amp draw, this will point you in the direction of where the fault is, depending on the draw.

Example: even though a cell phone charger doesn't draw much, and won't drain a battery overnight, the fact it is plugged in will still drain the battery, and depending on the condition of the battery, it very well could be dead by morning.

 

You can pull ALL the fuses out of the fuse block, and then do the amp draw test, adding back one fuse at a time to eliminate those ckts that are not using power.
Things that go bump in the dark: GEM module, door ajar/open switches inside the doors (Wd-40 to clean and free up), relays that stick in the 'on' position... just a few ideas.
But, measure the draw at shutdown, wait 20 min and re-measure. The GEM should shut down any lamp stuff after 20 minutes for sure...
tom

 

Well, this is just a guess, but I don't think my 1988 ranger has a GEM module.

Bigrig, how will determining the draw help me locate the problem?

By matching the draw to the ammount used by specific systems?

As far as I know, only the radio/clock memory is the only constant draw (by design). everything else I jumped into switched circuits (radio power, CB power, 12v accessory outlet).

note: this ranger had no power accessories from the factory. I've installed all of the above myself, but I'm really confident that I did so correctly.

I performed a continuity check by connecting a test light in series with the ground cable. my alternator guy said to then touch the ground cable and the test light tip to the terminal. the test light went out. alternator guy says this means the battery could be bad, even though it's less than 3 mos old.

I first noticed this problem after letting the truck sit a day. when I drove it every day, I didn't notice a problem. But with weather getting colder, I want to get it right.

 

by checking amp draw readings, it will tell you what a test light can't. Just because the test light goes out doesn't mean there isn't a draw. A draw can be small enough to NOT light the test light.
Pulling fuses while doing an amp draw is what I left out of my original post, so thanks for clearing that up. What I do is leave them all in, and pull one at time, that way if there is more than one fault, I will find them because the indicated draw may not completely disappear.
Once you find a problem circuit, check the whole circuit from fuse to ... well, whatever it is, say a light, or fan motor or whatever. Check the connections. If any look green, repace them. Check the insulation. If it looks cracked, broken or worn through, replace the wire with the SAME gauge wire, and preferably the same colour, using non-shielded butt connectors with heat shrink. Find a broken wire? Look for where it should go. Split wiring loom harnesses if you have to.
Maybe your alternator buddy needs his work verified. Nothing wrong with getting a second opinion. Obviously you are doing that by asking us here, with no practical way to test your truck for real.

Hope this helps.

 

Well, a divine hand may have helped me solve my problem.

After performing the continuity test, I went to tighten up the cable back on the battery post and herc'ed the bolt too much and broke the ring.

So I bought a replacement cable and when I went to reattach it, found a very oxidized contact where the battery cable joined the started cable.

I sanded both smooth and reconnected them.

The next morning, I didn't have a drain.

Unfortunately, there's no way to heat shrink the connection, as it bolts onto the frame. I plan to at least spray it with that contact sealer they sell at the parts store.

Thanks for all your advice. It seems like I was able to find the problem circuit due to my own stupidity over tightening the battery cable. But you were right on!

If I have another drain (or if this was just a red herring) I'll try again.

C-Z

 

hello cujozilla,
For what it's worth:
You saying that you replaced the battery mis-lead the respondents above into not thinking it was a oxidized battery terminal.

 

The terminals on the battery are fine.

I said the oxidized contacts were on a cable contact/junction where the starter lead contacts the battery cable, not the battery terminal.

when I went to reattach it, found a very oxidized contact where the battery cable joined the starter cable.

As it is, that was a red herrring (althought it did need tending)

After sitting two days while I was out of town, my ranger was stone cold dead again.

Am acquiring an ammetter.

 

Hi cujozilla,
Sorry for the misunderstanding, read your explanation wrong.

 

Hopefully, I've found an end to this problem, by replacing the voltage regulator. when I took it out (its an internal one), I found one of the alternator brushes had been broken off.

I've replaced the alternator and haven't had a problem since!