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Bad Alt, battery, or battery cables?


eREdge

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02 Ranger Edge 3.0L auto

So I been having this problem where the battery meter drops to Low. This doesn't happen every start up. Just 1/4 of the time. I've checked the volts with a multimeter and it reads anywhere from 11.8-12.3.v when the gauge is low. I had the charging system load tested and all checked out fine at the part store. I had the alt replaced anyways since a buddy of mine had a spare one lying around. The battery is only 2 years old, but I did have a parasitic draw that I fixed a month ago. Stays at 12.3v overnight. Same symptoms with the new alt, but it's been happening more frequently.* The battery terminals were also replaced.

I found that wiggling the alt and battery cables around will sometimes jump the gauge to the middle. Or restarting the truck will sometimes have the same effect. Reving the engine when the meter is low doesn't do anything.

Now, the battery cables themselves aren't in the best condition. The positive wires are stretched, frayed and over exposed. No corrosion. Cutting them back an inch won't have enough length for them to secure properly to the terminal. And the negative side looks ok with just a bit of corrosion.

I don't know how I would go about changing the cables. I did trace them, but they bundle up with a couple other wires in a harness and then bolts onto a a crimped terminal by the fusebox. Hopefully, its not as bad as it looks so any advice is appreciated.

I also want to add that the terminal posts themselves are clean and the new terminals aren't loose. The serpentine belt isn't loose either and was replaced sometime before I bought the truck(5 months ago).* The battery light does not come on when the meter is low. It does come on when I turn the key to the ON position. It doesn't have any effect on the lights either i.e no dimming
One connection (small white/black wire in-between the alt connector and power wire) on the alt does get loose sometimes. I thought it was a possible culprit so I pulled it while the truck was running and it didn't affect the gauge at all. It stayed in the middle. The tab on the plug broke off
 


RonD

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Battery is ONLY used for starting the engine.

New battery should read 12.8-13.0volts
3 years old 12.5volts
5/6years old 12.3volts and time to shop for new battery

But could be your volt meter is read low

Once engine starts the alternator provides ALL electrical power, and recharges battery for next start up
When engine is running "battery voltage" should read 13.5 to 14.8 volts no lower and no higher
Right after startup the voltage regulator in the alternator(3 wire plug) will run higher voltage, above 14volts but under 15volts, this is to recharge battery ASAP in case a restart is needed.
After about 5 minutes or so the voltage regulator will lower system voltage to 13.5 to 13.9volts, under 14volts, over 14volts for longer period will COOK a 12volt battery.

The GROUND is often overlooked in vehicle electrical systems, people focus on positive voltage, but there is no positive voltage unless there is 0 voltage(ground) for electricity to move thru devices.

On the back of the alternator is the B+ terminal, it should have Battery Voltage all the time.
First test battery voltage, say you get 12.3volts
Now test voltage at B+ using battery negative terminal as ground
Then test using Alternators metal case as Ground
Should be EXACTLY the same voltage
If not then Battery ground cable is a problem

Voltage gauge on the dash should go up after engine starts, system is going from 12.3v to 14+volts
Then after a few minutes it will go down a bit, 14.5v to 13.5volts for example
That is normal
Rolling up and down power windows should cause gauge to move, blower fan on high as well

Testing alternator Fields
After engine has been running at least 10min, you can test the 3 Fields
Do not turn off the engine
test battery voltage, leave meter connected, should see about 13.6volts
Now turn headlights on, blower to high and leave drivers door open(dome light)
Voltage will drop but then come back up to previous voltage, i.e. 13.6v in this example
If voltage is lower, 13.2v for example then you have one failed field, with meter still connected, raise RPMs and make sure voltage comes back up to 13.6v, this confirms one failed field.


White wire on alternator NEEDS to be working, connected and in good condition
It is the Stator wire and tells voltage regulator the status of the fields voltage
If unplugged alternator would still produce voltage but have no feedback for how much to produce.

An alternator doesn't generate voltage, it increases voltage
Voltage regulator sends 5 to 8 volts to the Rotor(spinning part), this creates a magnetic field around the rotor.
If engine is spinning the rotor then the stator(3 fields) will produce a higher AC voltage from the lower voltage magnetic field
So it increases voltage
AC Voltage is converted to DC volts via a pair of diodes on each field
So 6volts in gets 13volts out, 8 volts in gets 15volts out, its not a direct conversion since alternators RPM changes, which is why the white stator wire is important
 
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eREdge

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Battery is ONLY used for starting the engine.

New battery should read 12.8-13.0volts
3 years old 12.5volts
5/6years old 12.3volts and time to shop for new battery

But could be your volt meter is read low

Once engine starts the alternator provides ALL electrical power, and recharges battery for next start up
When engine is running "battery voltage" should read 13.5 to 14.8 volts no lower and no higher
Right after startup the voltage regulator in the alternator(3 wire plug) will run higher voltage, above 14volts but under 15volts, this is to recharge battery ASAP in case a restart is needed.
After about 5 minutes or so the voltage regulator will lower system voltage to 13.5 to 13.9volts, under 14volts, over 14volts for longer period will COOK a 12volt battery.

The GROUND is often overlooked in vehicle electrical systems, people focus on positive voltage, but there is no positive voltage unless there is 0 voltage(ground) for electricity to move thru devices.

On the back of the alternator is the B+ terminal, it should have Battery Voltage all the time.
First test battery voltage, say you get 12.3volts
Now test voltage at B+ using battery negative terminal as ground
Then test using Alternators metal case as Ground
Should be EXACTLY the same voltage
If not then Battery ground cable is a problem

Voltage gauge on the dash should go up after engine starts, system is going from 12.3v to 14+volts
Then after a few minutes it will go down a bit, 14.5v to 13.5volts for example
That is normal
Rolling up and down power windows should cause gauge to move, blower fan on high as well

Testing alternator Fields
After engine has been running at least 10min, you can test the 3 Fields
Do not turn off the engine
test battery voltage, leave meter connected, should see about 13.6volts
Now turn headlights on, blower to high and leave drivers door open(dome light)
Voltage will drop but then come back up to previous voltage, i.e. 13.6v in this example
If voltage is lower, 13.2v for example then you have one failed field, with meter still connected, raise RPMs and make sure voltage comes back up to 13.6v, this confirms one failed field.


White wire on alternator NEEDS to be working, connected and in good condition
It is the Stator wire and tells voltage regulator the status of the fields voltage
If unplugged alternator would still produce voltage but have no feedback for how much to produce.

An alternator doesn't generate voltage, it increases voltage
Voltage regulator sends 5 to 8 volts to the Rotor(spinning part), this creates a magnetic field around the rotor.
If engine is spinning the rotor then the stator(3 fields) will produce a higher AC voltage from the lower voltage magnetic field
So it increases voltage
AC Voltage is converted to DC volts via a pair of diodes on each field
So 6volts in gets 13volts out, 8 volts in gets 15volts out, its not a direct conversion since alternators RPM changes, which is why the white stator wire is important
Ok so I did some testing and had no voltage drop in the ground test of the battery and alternator, so that rules out the negative cables.

On first start up, the multimeter was reading 12v, gauge on low. I restarted the truck and it didn't change anything so I decided to mess around with the alt cables again and the truck revved itself to 2k rpms and it stayed there constantly and was running rough. The multimeter read 14v. i turned off the truck and tried again.

Finally, it started normally, with the gauge in the middle and meter reading 14v. I turned on all accessories plus I have two amps and a subwoofer. This time the multimeter was reading 13.1-13.3v and reving it raised the volts to 14v.

Knowing this, why doesn't the gauge move at all sometimes when it reads low and reving the engine? I pulled in to work yesterday and the gauge immediately dropped to Low. Revving the engine or even driving down the road had no affect. It's been doing it more often so maybe the alt is failing? I was planning on installing a bigger alternator anyways but I'm still not 100% sure if the cables are coming into play as mentioned earlier.

Side note, I was gonna scan the computer for codes but the fuse for that is blown. I believe it's #19 25A Fuse not sure if that would affect anything in the charging system. I'll pick up the fuse when I have the chance.
 

RonD

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On the back of the driver side head there should be a Ground strap that is bolted to the Firewall, this is a Main Ground for the cab.

When any engine work is done this is often left hanging, not reattached.
You would think with all the metal parts bolted together that the cab would be grounded, but....all baby parts are painted FIRST, and then bolted together, and usually with rubber washers or spacers, so not great grounds, which is why the strap is there.

Find it and make sure it is tight, and a good ground
Can be on passenger side head as well.
 

det107

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Move over eREdge..... And RonD, help me~
My truck just started having a no start problen also. The first time the cluster panel lit up & turning the key didn't do a thing but click. At the time I was in a hurry so I pushed & pop started it, no issues driving & making deliveries (left it running)
Following next day, no start. Same usual push & pop clutch. I made a 20 mile trip & had to shut it off until business was concluded. On the return trip(again the push & pop routine), it was getting dark do I put on the headlight switch...For some reason, temp spiked a bit, battery gauge meter dropping & headlights dimming.
I took it to the shop next day & "starter was the culprit"...Owner booted me out w/instructions to R/R on my own...
Get this, I was able to turn key afterwards to start. I did go over to the local rebuilder and to my surprise, he was out of business. Since it was easy to start again, I was back to the same old grind. I had to go make another 20 mile trip, no start again(!), push & pop....temp gauge, battery meter & headlights dimming.

So I got a new battery, reman alternator & reman starter...Problems exists like first time it's okay to push & pop but once it shuts off (turned off), the second time around makes everything go erratic.

I do have an shop appt Friday morning though. I have a feeling that both transponder keys are bad?
 
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eREdge

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On the back of the driver side head there should be a Ground strap that is bolted to the Firewall, this is a Main Ground for the cab.

When any engine work is done this is often left hanging, not reattached.
You would think with all the metal parts bolted together that the cab would be grounded, but....all baby parts are painted FIRST, and then bolted together, and usually with rubber washers or spacers, so not great grounds, which is why the strap is there.

Find it and make sure it is tight, and a good ground
Can be on passenger side head as well.
Ok Ron I'll go ahead and sand down and tighten all the other ground connections I can find while I'm at it. You seem confident that it's a grounding issue and hopefully it is. I'll let you know how it goes
 

RonD

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Well you had/have two different problems, not one

Battery is ONLY used to start the engine, and it must sends 70 AMPs thru positive cable to starter motor and GET BACK 70 Amps thru Negative cable(actually the other way around but thats another story, lol)

So Battery wasn't able to send 70 amps to the starter motor OR wasn't able to get 70 amps back, simple and as complicated as that.

So check larger battery cables at BOTH ENDS they handle the high amp stuff
Pay attention to Negative battery cable, needs a GOOD CLEAN connection on engine bolt.

Starting system has TWO starter relays in 2002, well around 1998 and up i think.
One is in the Engine fuse box, labelled............starter relay :)
This relay is activated by the key turned to START, if in your case clutch pedal is down all the way.
But this relay may not work if THEFT Light is Flashing rapidly, you don't mention that so the "click" you heard when key was turned to START was probably this relay working like it should, and PATS key is fine.

Now the second starter relay, its in the starter motor, well sitting on the starter motor.
It is a relay/solenoid.
When engine fuse box relay closes this Second relay gets 12volts and closes, this moves the solenoid which pushes out the starter motor gear AND connects the large positive battery cable on the starter motor to the motors rotor, and off she goes ......if starter motor has a GOOD GROUND!

Electricity is like a one lane circular road, you can only go as fast as the slowest driver, you may want to go 70 but if there is a 30 driver then EVERYONE slows down to 30

Alternator supplies ALL electrical power once engine is started, ALL electric power
It runs the system at minimum 13.5volts
Brand new battery is 12.8volts, maybe 13.0v
So battery PULLS IN the higher voltage from alternator to keep itself charged

Battery is out of the picture in other words, it is needed to 'smooth' voltage, but is no longer supplying any voltage to the vehicle.

So you had an alternator problem if gauge was jumping around and lights were dimming, and you need a Volt Meter to test this stuff even with new battery and alternator, especially with new battery and alternator, lol.
NEW just means NEVER TESTED, so you need to test it
Alternator problem could be a fuse or fusible link or a GROUND
Alternator needs to put out minimum of 40amps, 60-70amps when everything is ON, so you got that Ground thing, and the slow poke driver, bad connection
 
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det107

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Thanks RonD-
 

eREdge

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Alright just a quick update

I sanded the main ground as well as other grounds that I could find and tightened them all down properly.
I also cleaned both the positive and negative wires with a wire brush. The negative terminal bolts that clamp down the wires weren't as tight as I thought they were, in fact I could've probably loosened them by hand if I wanted lol oops

I've started the truck about 5 times today and all is normal. I don't want to confirm anything just yet though. I'll give it about a week or two but hopefully my problem is resolved.

Thanks again Ron, ill post again if my problem persist.
 

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My credo
to prevent Found On the Road Dead, Fix Or Repair Daily
My rule for parts R+R when chasing gremlins is to start with the cheap easy. stuff. Often that is inspecting and cleaning stuff no money, just time. I also know that anything I fixed is suspect. I 'm not a gifted mechanic. I've humbled myself enough times to prove that to myself. :D
 

det107

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Move over eREdge..... And RonD, help me~
update.....and sorry for threadjack.

The solenoid terminal wiring (for starter) was "bad" below the crimp & new eye terminal w/wider clasp was replaced. Much better & no weird problems cropping up.

Andy is right about R/R smaller parts. That's exactly what I should have done unstead of checking, cleaning/sanding & taping/gluing solenoid wire. It still lit up the test light though :dunno:
 

eREdge

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Just a quick update

I haven't had this problem once since and can conclude it was a grounding issue. Thanks Ron!
 

RonD

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Good work :icon_thumby:

Thanks for posting the update and the fix
 

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