When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Well, is it a problem? I don't know, that's why i'm asking. Yes, I will check the voltage soon, just wanted to ask first to see what more it could be and also to learn about electrical. This can't be that hard right?
So it rained here in SoCal for 2 days and starting on first day, I noticed my battery light went on and as I'm driving, I noticed my battery guage was like around 9-10V. But I'm still driving. Battery is pretty new, on warranty from Costco around August so it's good.
Here's the symptoms: I put key in, turn in on, and it starts up right away! So what I learned over the past few years is that battery has to be about 12V in order to start the engine. So far so good, but gauge is saying like 10, and light is on. I then keep it on PARK and rev the engine good, like 2 or 3 pumps of the pedal and sure enough, it creeps up to 12-14V. Just where it is supposed to be.
That was good for a day but last night and this morning, I tried the vroom vroom method, and the guage is still around 9-10 and the light is still on! It starts out fine, there is no eek eek eeek sound like you get when you say "oh dang, my battery is dead
, radio works, light works, nothing seems amiss.
So my question is, what is that gauge and light attached to? The battery or the alternator? What exactly is it reading?
BTW, I watched Chris Fix video and I'll try to get the numbers tonight, Also, no clue how old my alternator is.
2nd question, can Oreilly or other car stores do an alternator check? I think AAA has done it when I needed a jump.
Possible alternator failure, it happens to all eventually. I'd lean toward battery post corrosion, but it is still starting with low voltage, so that still could be but seems less likely. Most chain Autoparts stores will test them for free, but to test just the alternator it will need to come off.
So my question is, what is that gauge and light attached to? The battery or the alternator? What exactly is it reading?
Don't know where exactly everything is connected, but the voltmeter shows the volts on the system, and the light shows that the battery is discharging.
Typically like to see 12.8 - 14.5 volts when running. A fully charged battery should show about 12.6 volts, engine off. Offhand, suggest the voltage regulator within the alternator has failed.
Ah, for the good ol' days with an ammeter on the instrument panel. We know what happened to them when automakers found that voltmeters were cheaper... :-)~
Offhand, suggest the voltage regulator within the alternator has failed.
Ahhhh, interesting. Now I learned a part of the alternator and I didn't know about. "Voltage regulator!". I think I can remove the battery out of the equation since it is just a few months old. Hmmm, I leaning towards either bad connection to the alternator or for some reason, the rain was just a coincidence cause sometimes, I hear, moisture and rain can do weird things electronically. Then as I'm driving, I'm like "wait, the engine is HOT so it should dry things up".
I'll check out some vids on testing alternators today and see if I can perform it tonight, in the dark'ish carport that I have.
If it is an Alternator, if not Motorcraft brand...what's the next good one? Bosch? New? Reman? And what brands to avoid?
Some voltage regulators, especially on older vehicles, were external, mounted on the firewall or similar. With most nowadays being internal, usually not worth the time and effort fooling with, just replace the alternator.
New is nice and preferable, but reman is more practical. Can't really specify names, just advice to not go cheap and to compare warranty lengths. Not that warranty is everything - had a lifetime AutoShack (now AutoZone) warranty, went through three or four before I got one that lasted. Warranty kind of lost its luster after the 2nd changeout, but it was cheap and they made good on every one.
An alternative would be if you have a starter/alternator shop in town. Here, can take the alternator in and most times they rebuild it right there while you wait - gets new bearings, diode pack, brushes, stator windings, etc. with pretty good quality parts and ballpark competitive prices.
An alternative would be if you have a starter/alternator shop in town. Here, can take the alternator in and most times they rebuild it right there while you wait - gets new bearings, diode pack, brushes, stator windings, etc. with pretty good quality parts and ballpark competitive prices.
Yeah there's a place in town here that does alternators/starters, last time i used them it cost 100 bucks.
Of course - that's why it turns on a RED light on the dash. If it was just a warning, it would be amber/yellow. If it was OK/normal operation/just FYI, the light would be green.
Originally Posted by ericantonio
Yes, I will check the voltage soon...
You can see it right there on the volt gauge in your photo. It's low, but still not outside the "normal" zone, which means the truck should start & drive. But it's lower than it should be when the alternator is supplying electrical power, which means you're driving on the battery ONLY. When the battery goes dead, so will the truck. You need to charge it (but NOT a fast charge) all night, each night, until you get the alt fixed. Preferrably in the 0.5-3A range, using a true float charger. The only ones I use are BatteryTender brand.
Originally Posted by ericantonio
...to learn about electrical.
The caption of this diagram explains most of what there is to know about that alternator, and the charging system on your truck. There are more links in the caption for more info.
Well... Electricity seems to be the hardest thing for people to comprehend. Including successful professional automotive technicians who make electrical repairs every day. So don't be surprised if you don't grasp it fully just through the course of this thread.
Originally Posted by ericantonio
...I noticed my battery light went on...rev the engine good, like 2 or 3 pumps of the pedal and sure enough, it creeps up to 12-14V. Just where it is supposed to be.
Did the light go out?
Originally Posted by ericantonio
...there is no eek eek eeek sound like you get when you say "oh dang, my battery is dead
I usually associate "eek eek" with a slipping drivebelt, or a bad alternator/smog pump/compressor bearing. To me, the sound of "dead battery" is a single click, or no sound at all.
Originally Posted by ericantonio
what is that gauge and light attached to?
The gauge is attached to the charging system, through the ignition switch & the body grounds. The light connects the positive side of the charging system to the alternator voltage regulator "I" (Indicator) input. If the input is ~12V+, the alternator assumes the key is on, and it should be trying to charge. If the VR detects a fault, it grounds that terminal, causing the light to come on.
Originally Posted by ericantonio
What exactly is it reading?
The gauge reads charging system voltage; and the light shows a failure in the alternator or VR.
Originally Posted by ericantonio
Also, no clue how old my alternator is.
Well, the age of the truck is a clue, isn't it?
Originally Posted by ericantonio
can Oreilly or other car stores do an alternator check?
That's a loaded question... Parts store employees are NOT technicians. Most of them are not even ASE-certified to look up parts (yes, there are tests & qualifications). Do most of the stores have the equipment to check an alternator? Yes. Do most of the employees actually know what they're doing well enough to use the equipment? My opinion is NO. But you don't really need them. If you read the caption of that first diagram, you can test the alternator yourself without even removing it from the truck.
Originally Posted by ericantonio
I think I can remove the battery out of the equation since it is just a few months old.
Not because it's new; but because the truck still starts. New batteries CAN be bad, and often are (for a wide variety of reasons). Especially house-brands (like Costco), sold under stickers of companies that don't manufacture batteries (like Deka) or supply them as OE in new equipment (like Ford). Those batteries are built to lower standards - whatever the sticker company wants to sell to its customers. Not to the standards that the actual manufacturer or OE brand would specify for its own batteries.
Originally Posted by ericantonio
...leaning towards either bad connection to the alternator...
It's very UNlikely that either alternator connector has failed. The only wiring fault I can imagine that would produce this symptom would be under the rear edge of the battery, where the alternator wiring harness connects to the engine bay harness. There's a single small LG/R wire in a large round connector which might become pinched or corroded, producing this symptom.
Originally Posted by ericantonio
I hear, moisture and rain can do weird things electronically.
Yes, but everything in the engine bay is designed to tolerate heavy road spray. Including the alternator, VR, & battery. Only the belt can be briefly interrupted by lots of water.
Originally Posted by ericantonio
If it is an Alternator, if not Motorcraft brand...what's the next good one? Bosch? New? Reman? And what brands to avoid?
That's a lot of "ifs" to worry about before you've actually diagnosed the problem. I doubt Ford/MotorCraft still offers fresh reman 3G alternators. But the ones in the junkyards are usually still good, and MUCH more affordable than anything from a store. You can also find fresh remans on junk trucks, making them equally-affordable, and possibly more-desirable. Big names like Bosch are likely to use better parts, but it's no guarantee. Just stay OUT of the zone, and any other discount consumer-grade parts stores.
Originally Posted by wde3477
With most nowadays being internal...
The 3G's VR is external, and VERY easy to R&R. That caption explains how. It's also still available new, but it's more-likely the brushes (which are attached to the VR & available new) that have worn down.
Originally Posted by wde3477
New is nice and preferable...
No one still produces 3Gs new. They're all either reman or used.
Originally Posted by wde3477
...just advice to not go cheap...
I agree - particularly about the zone, which is my vote for the WORST parts supplier possible.
.Did the light go out?I usually associate "eek eek" with a slipping drivebelt, .
Yes the light went out after I pumped the gas a few times.. I guess eek eek eek was bad description
I mean, whirl whirl whirl when you try to start a car with a bad battery.
Haha, Yeah, I guess the voltage reading IS RIGHT THERE!!
Well, guess the time is right to get a new Alt. Also, age of car...I'm like #3 owner at least so she's been around the block, had puppies, in retirement, by the time I got to her.
I just saw one at RockAuto. About a buck and a half for a rebuilt OEM Motorcraft one. Not really sure how long I'll have this but probably cost more or less the same for a cheaper brand at a local car store.
Let me try Amazon and some other brands like Bosch. Guess you can't go wrong with the big name ones. I'm just a little put off with the rebranded big car store brand names ones.
So basically its: disconnect battery from terminals, disconnect from ALT, I think its 4 bolts, disconnect belt, and repeat process backwards right? Nothing fancy here?
Last edited by ericantonio; 01-10-2018 at 07:44 PM.
Whew, Steve83 is a wealth of information there. :-)
Yes, IMO, alternator replacement is pretty straightforward, hardest part for me was getting the serpentine belt undone and then reapplied. Definitely be sure to lift the negative post on the battery!
FWIW, don't know which model years it applied to, but there was a problem with the power connector going into the alternator, with my replacement alternator supplying a replacement connector to be soldered in place of the original. Dunno if it really needed to be done, but like a good little camper, I did it. The original didn't show any signs of fatigue or heating.
Whew, Steve83 is a wealth of information there. :-)
Yes, IMO, alternator replacement is pretty straightforward, hardest part for me was getting the serpentine belt undone and then reapplied. Definitely be sure to lift the negative post on the battery!
FWIW, don't know which model years it applied to, but there was a problem with the power connector going into the alternator, with my replacement alternator supplying a replacement connector to be soldered in place of the original. Dunno if it really needed to be done, but like a good little camper, I did it. The original didn't show any signs of fatigue or heating.
Thanks!!!
What's sucks is that Amazon has them but won't be here til next week wed/thurs.
I know I can go to a local and yes, I shouldn't get an AZ brand. Ugh.
Well, it's socal so I'm sure if I look hard enough, I can find a good one locally before I go web order.
01-10-2018, 11:53 AM
I have a good challenging battery light problem
If it was just a warning, it would be amber/yellow. If it was OK/normal operation/just FYI, the light would be green.You can see it right there on the volt gauge in your photo. It's low, but still not outside the "normal" zone, which means the truck should start & drive. But it's lower than it should be when the alternator is supplying electrical power, which means you're driving on the battery ONLY. When the battery goes dead, so will the truck. You need to charge it (but NOT a fast charge) all night, each night, until you get the alt fixed. Preferrably in the 0.5-3A range, using a true float charger. The only ones I use are BatteryTender brand.The caption of this diagram explains most of what there is to know about that alternator, and the charging system on your truck. There are more links in the caption for more info.
Electricity seems to be the hardest thing for people to comprehend. Including successful professional automotive technicians who make electrical repairs every day. So don't be surprised if you don't grasp it fully just through the course of this thread.
Did the light go out?
I usually associate "eek eek" with a slipping drivebelt, or a bad alternator/smog pump/compressor bearing. To me, the sound of "dead battery" is a single click, or no sound at all.The gauge is attached to the charging system, through the ignition switch & the body grounds. The light connects the positive side of the charging system to the alternator voltage regulator "I" (Indicator) input. If the input is ~12V+, the alternator assumes the key is on, and it should be trying to charge. If the VR detects a fault, it grounds that terminal, causing the light to come on.The gauge reads charging system voltage; and the light shows a failure in the alternator or VR.Well, the age of the truck is a clue, isn't it? 
That's a loaded question... Parts store employees are NOT technicians. Most of them are not even ASE-certified to look up parts (yes, there are tests & qualifications). Do most of the stores have the equipment to check an alternator? Yes. Do most of the employees actually know what they're doing well enough to use the equipment? My opinion is NO. But you don't really need them. If you read the caption of that first diagram, you can test the alternator yourself without even removing it from the truck.
Not because it's new; but because the truck still starts. New batteries CAN be bad, and often are (for a wide variety of reasons). Especially house-brands (like Costco), sold under stickers of companies that don't manufacture batteries (like Deka) or supply them as OE in new equipment (like Ford). Those batteries are built to lower standards - whatever the sticker company wants to sell to its customers. Not to the standards that the actual manufacturer or OE brand would specify for its own batteries.It's very UNlikely that either alternator connector has failed. The only wiring fault I can imagine that would produce this symptom would be under the rear edge of the battery, where the alternator wiring harness connects to the engine bay harness. There's a single small LG/R wire in a large round connector which might become pinched or corroded, producing this symptom.Yes, but everything in the engine bay is designed to tolerate heavy road spray. Including the alternator, VR, & battery. Only the belt can be briefly interrupted by lots of water.
That's a lot of "ifs" to worry about before you've actually diagnosed the problem. I doubt Ford/MotorCraft still offers fresh reman 3G alternators. But the ones in the junkyards are usually still good, and MUCH more affordable than anything from a store. You can also find fresh remans on junk trucks, making them equally-affordable, and possibly more-desirable. Big names like Bosch are likely to use better parts, but it's no guarantee. Just stay OUT of the zone, and any other discount consumer-grade parts stores.The 3G's VR is external, and VERY easy to R&R. That caption explains how. It's also still available new, but it's more-likely the brushes (which are attached to the VR & available new) that have worn down.No one still produces 3Gs new. They're all either reman or used.I agree - particularly about the zone, which is my vote for the WORST parts supplier possible.