So passing on the ranger to the youngest kid; it's had it's share of electrical issues; but lately seems pretty stable.

So this weekend we swapped out the radio for an upgrade; everything seems fine. Drive around the next day, still good, so he goes to school today, started fine this morning; but battery was dead after school, jump started just fine; then it was dead again after practice (4hrs later); again jump, drive home.

I go out to look it over, figure he left the headlights on or something stupid; nothing obvious, go to start it (5 min after driving) and it's dead, ~9.5V, battery is only like 3-4 months old

So I put the meter into Amps, and key out, doors closed, lights off I'm seeing a .33 - .5A draw (it switches back & forth but stays on .5 most of the time)
I assume the computers need some power, but that much? With the door open (dome light on) it draws ~2.5A

Disconnected the radio completely (well removed the cable harness from the back of the radio) and its still drawing .5A

Before just pulling random fuses, any suggestions where to start?

Running its reading 14.5V, so Alt should be good

 

Alt is fine. A draw of half an amp is INSANE. You've got a paracidic draw going on. You ought to be seeing somewhere in the ball park of 10 to 70 milliamps. 70 is a little high, but that's what mine is close to.

Your only real option is to start pulling fuses and watch for the change.

 

The 1995 and up Rangers have a Battery Saver Relay, so it is hard to check amp draw at the battery since this relay stays closed for 20 to 30 minutes after key off/out and doors are closed.
So the .5amp is not that unusual unless you wait.
.03 to .05 is spec draw after Battery Saver relay opens.


BUT..........battery saver relay could be the problem if it is not opening after 20-30 minutes

 

Thanks, so what if I just pull the battery saver relay out? Then if something is left on, it won't 'protect' the battery right?

I figured I was going to have to do the fuse pulling, was hoping maybe narrowing it down to a few.

I don't think the radio is the problem, we replaced it Fri afternoon, it already had an aftermarket one installed, I just swapped the wires to the new radio. We didn't drive it sat, sun we took for a short drive, and it started mon morning. It wasn't until after that drive it keeps dieing.

Could be a short somewhere too, I've have the issue of trying to start it, it clicks once, and the whole truck is dead, no lights, nothing. Pull a batt cable off, it resets, and sometimes it starts, and sometimes it takes a few resets. I replaced the batt terms and haven't had that issue lately, but I can see the neg wire at one point has been spliced about a foot from the battery, to far away to just connect it, will probably eventually need to replace it.

 

OK, so got to pull every fuse/relay in the dash/under the hood, dr side box (anyplace else?)
SO the only ones that dropped the draw was inside fuse # 25&26, both point to GEM, outside maxi #1, which I think just powers the inside panel.

On the GEM (driver side of radio cavity?) if I unplug the top bunch of wires/conector the draw also goes away; how do I track down what in that huge mess of wires is the culprit?

Guess I need to get the battery checked out next.

 

GEM will draw power until it shuts itself off after 20-30minutes, nothing you can do to change that, it opens battery saver relay when it shuts off.

Now you could connect amp meter to battery cable and battery post, then also use a jumper cable from battery cable to post.
Cycle key on and then off, jumper cables handle the amps for that, not meter
Remove one end of jumper cable and you should see the .5A draw, now wait 20-30 minutes to see if, amps drop, GEM shuts off, make sure doors are closed of course

 

Something I thought about, half an amp shouldn't kill the battery over that period of time. 4 amps takes quite a while, and I know that from experience. So .5 would take 8 times as long.

When you jump the vehicle, are you giving the battery enough time to charge? If it doesn't have enough time to charge up, it'll never start the vehicle. Throw a trickle charger on 'er over night if you haven't already.

And yes, I would replace that battery cable. Corrosion could be a problem.

Also, check where the battery connects to the truck. If those are crusty and dirty, it won't stand up to the power you're pulling. Clean 'em, tighten 'em, make sure they're good. If they're fine, then great.

If they're the lead battery terminals where the wires are basically bolted on, check those wires and make sure they aren't crusty either. Those battery terminals are pretty crap in general, but they get the job done, I guess.

 

OK Thanks for the tips... so took battery to Ford (where I bought it) and it tested bad cells; so I got a new one!

Got a GEM from the junkyard, but it's lacking power windows, and 1 connector with 2 wires on my old GEM.

But for not I put the original back in, draw seems to be normal, .4ish right after key out, .01 after 30min.

So lets hope it was that easy!

 

Yes, normal

Good work

Thanks for updating the thread and posting the fix

 

Awesome, glad it was just a battery issue instead of some expensive rabbit hole

 

Just as a heads up if you check this thread again.

Check the charging system, there may be a problem there that caused battery to fail.

Battery voltage should be 12.3 to 12.9volts key off
After starting engine battery voltage should be 14.3-14.9volts, this is called "Recharge voltage".
Voltage regulator recharges battery after starter motor drained it, but voltage above 14volts is bad for the battery long term, it "boils" away chemicals in the battery.
So after a few minutes(under 5min.) voltage regulator will drop voltage to 13.6volts, this a "Maintenance voltage", keeps battery charged but doesn't "cook it".

When voltage is 13.6v and engine is idling, turn on head lights and fan blower to high, leave door open, voltage should drop as each power draw is activated and then come back up to 13.6v, this is voltage regulator "seeing" the extra power draw and responding by increasing alternator output.

What you learn
If voltage stays above 14volts then new battery will suffer same fate as last one, shorted cells.
Replace alternator.

If voltage drops below 13.2volts as lights and fan come on then 1 Field in the alternator is bad, if you increase RPMs the voltage will come back up, but alternator will need to be replaced at earliest convenience, funds permitting, no big rush.
Common thing most people notice first with this is Head lights dimming at idle.
No car maker specs in an alternator that can't produce enough voltage at idle to power all electrics in a vehicle.
So the dimming lights means 1 of the 3 fields in the alternator has failed, you don't lose 33% of alternators voltage output, above 1,200rpm the 2 remaining fields can generate the 13.6volts, and since most driving is done above 1,2000rpm the battery will stay charged, so not a big deal but...........it doesn't mean time to shop for another alternator

 

Thanks for the detailed TS steps, I only tested 'charging' voltage is 14.5ish V, so I assumed Alt is good, will do those steps when I can.

It started just fine this morning, didn't check voltage; but the dome light was bright vs dim on the old batt.

 

The important one is the Maintenance Charge, 13.6volts after 5 minutes or so.
If alternator stays at 14+ volts your new battery will be toast in no time at all.

Best thing is to leave it running after driving home or ??, and then pop the hood and test voltage at that time.

 

Well I got a chance this morning to play with it.
14.6 no matter what. After 5-10min, turn on lights, fan, dome lights, etc, 14.6 the whole time.

So is there a separate voltage regulator, or is it all alternator?

Separate question, should the AC compressor kick on & off frequently, even with heat selected and 50f outside?

 

I'm pretty sure the voltage regulator is inside the alternator. RonD / TAW: please chime in here if I am wrong.

As for the AC on/off frequently: if you turn on the defroster, it will cycle the AC on and off (I believe to remove moisture). Mine kicks in and out regardless of the outside temp if in defrost position. I haven't noticed it doing that in just heater mode.

 

The reason it does this, and the whole reason it works, is the AC unit kicks out some seriously dry air, which as a result removes the moisture on the windows/windshield. I don't have an exact answer for why the frequent cycling, but I'd suggest it would be to prevent the air from getting so cold that it would defeat the purpose of the heater.

I believe it also cycles to prevent it from seizing during the winter.

 

Voltage regulator is in the alternator and most can be changed, disconnect battery remove alternator and then remove the voltage regulator.
Take it with you to parts store to get exact replacement.

Most replace the whole alternator, I get mine from wrecking yards, lol.
Because when voltage regulator fails it can mean other parts of alternators electrics might be the problem or have been damaged.

Yes that 14+ volts is what "cooked" the last battery, surprised Battery Seller didn't want to test your charging system when replacing the last new one.

Example of voltage regulator here: http://www.ebay.com/itm/VOLTAGE-REGU...-/281040761645
The rod is holding the brushes up so it can be installed, then it is removed


Yes, AC system is used to dry the air in the cab, the principle is the "cold glass of beer on a warm day".
Water collects on the outside of the cold glass, why?
Warmer air can hold more moisture than cooler air, as the warm air comes into contact with the outside of the cold glass it cools down and since it can't hold the moisture it is deposited on the outside of the cold glass.
Same thing happens inside a car/truck on a cold day, the glass gets cold and when the warmer air inside the vehicle comes in contact with the cold glass it leaves its moisture behind, fogged up windows.

Vehicles without AC still Defrost windows by blowing warmer air, which can hold more moisture, across the cold windshield, and the warmer air 'picks up' some the moisture and warms up the glass so it doesn't get more moisture.

AC allowed for faster working Defrost because of the "cold beer glass" principle.
The air being blown in to heater core passes thru the AC's evaporator first, if evaporator coils are cooler than the air then moisture will be pulled out of the incoming air.
This drier air is then heated by the heater core making it very "dry", so it literally sucks the moisture off the inside of the windshield.

Yes AC would cycle on and off for this because its purpose is not to cool down the cab just remove some of the moisture from in coming air to make Defrost work better.

 

Well the Ford tech didn't know what to do when I just brought in a battery w/o the vehicle, scratched his head for like 5 min.

So probably a good thing I didn't have it, I'd be out a battery & ford price on an alt.

I think I'll replace the whole alt, $80@ rockauto, vs $45 regulator.

As for AC, it's done it since I bought it 3 years ago, even recently had the AC system filled to proper weight. Just curious if it's normal. I mean it's like every min it kicks in for several seconds, then off for a min, maybe 2. AC blows cold. I need to repair the max ac vac line somehow, it snapped on half under the hood, not sure how far past the firewall it goes.

 

Battery would still be replaced under warranty, the check of the system would be so they didn't have to replace the next new one, lol.


MAX AC just closes Outside air vent, so cab air, which is already cooled down, is recirculated.
On some models it also closes a valve on the heater hose so heater core in the cab cools down, even though it is not being used the heater core will still be warm from coolant circulation, shutting off flow makes it cooler.

Yes, cycling AC compressor can be normal, but turn off system, and move vent control off of Defrost to see if cycling stops