How to change an alternator: alternator not charging, diagnose and replacement

#alternator #lowvoltage #deadbatteries
In this video i will cover how to replace an alternator. I'll show a couple simple checks you can do to see if your alternator is charging, and verify your voltage at the alternator and batteries. It is not complicated and can save you a bunch of money. You need only basic hand tools.

[@DIYSEMI]

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[@Hearmeout503]

I CAN REALLY LEARN SOMETHING FROM THIS GUY ! VERY INFORMATIVE !

[@reality2737]

Bro you have no idea, how much you are helping me. Thanks 🙏

[@michaelcongilio7484]

Excellent. Straight to the point. Your good.

[@ericclayborn7929]

Important: For those who don’t know. The Alternator “shroud or fan blade” SHOULD NOT MOVE!!! It should be secured to the pulley after tightening of the nut!

[@michaelbritton2331]

great video thanks for the time taken to make it.

[@baclieustud]

going to do one tomorrow,,thanks for your video

[@alexshortsplus]

You make it look so easy 😄👍

[@albethel3027]

Awesome video. This really helped me out. Safe travels.

[@aaronpeddicord2944]

Yes sir great video

[@TheBlacktygar]

Very detailed

[@JoseHernandez-lm3hs]

Excellent Great explanation and quality Thanks brother

[@jdmoving399]

the two small cables what are they for?

[@able880]

@@jdmoving399 one is to energize the altenator when the key is turned on or if there is a oil pressure switch used when the engine oil pressure comes up it energizes the altenator and it starts generating power - the other is for a light that is on the dash or for the computer on the truck - it lets the driver or operator know that the altenator has no out put or it has failed -

[@simonqian9300]

great job

[@DIYSEMI]

👍👍👍

[@rronmar]

Nice video. Thats not a horrible voltage, standard automotive alt spec is 14.5 +/- 0.5, but for long term running it is a little high. Does that alternator use remote sense? If it does, perhaps that sense line has become disconnected somewhere. you could connect it to the B+ terminal, which would lower the voltage at the batteries…

[@kimroyful]

I've never seen anyone open up these alternator

[@excavatoree]

You may want to invest in a universal puller. Yes, you won't need one much, but they are inexpensive enough to justify owning one so you don't have that hassle.

[@DIYSEMI]

I agree, that would be the smart thing to do. I also want to learn how to weld

[@JoseRodriguez-xz7qm]

I have a 09 cascadia dd15 and I replace 4 new batteries and after 4 days of not going to work it drain all my juice of the batteries. any help on where to start looking for the problem? thanks

[@Mohammedfromchicago]

15:11 what do you call this long iron part that you are using for loosening and tightning the belt please?

[@MahA-pr7kr]

Thank you for this video. the truck battery got down because the alternator was not charging. How long should take to charge the truck battery in full after I replaced the alternator?

[@DIYSEMI]

you really should use a charger to charge the battery back up. if it is too dead you could possibly damage the alternator on startup

[@ChristianTrucker]

This vids electric 😎🇺🇸

[@DIYSEMI]

Haha. Thanks! Be safe

[@angelmartin4519]

Not sure you’ll reply in time but would a bad alternator cause truck to just shut off middle of the road going about 55?

[@DIYSEMI]

not likely

[@whitetailfox1]

Some of the revised models of alternators are about .5 amps higher

[@thadiesel7655]

With truck running, voltage is 14.1.. if i run over very rough road, the voltage temporarily jumps up and fluctuates between 14.1 and 17.. then after a while, normal. Also happened once when I ran thru need water. Do you think I have loose connections somewhere? I know connections at battery and alternator are good. Where else might I check? 2019 cascadia

[@DIYSEMI]

Sounds like the regulator in the alternator

[@thadiesel7655]

@@DIYSEMI ok thanks. I considered that also. But second guessed myself because it only happens when going over a big bump or high water.

[@markrob9752]

Have low voltage issues, had my alternator tested reading 14.6 volts and loaded 13.8...Brand new batteries and check wires from battery to starter from starter to alternator all good reading. I'm stumped what my issue is...Also replace negative cable from alternator to starter still no luck

[@DIYSEMI]

14.6 kinda high. Doesn't costantly jump all over? More than the usual 13.8 to 14.1 ? I guess I don't understand your whole problem

[@markrob9752]

@@DIYSEMI I'm getting low voltage, I check everything I possibly can check. Wires etc, had Alternator tested off the truck..reading 14.6 on machine and loaded on machine 13.8...My truck is reading 13.3 on dash and goes up to 13.6 then back down..When I drive it pressing the break it drops to 12.7 then goes back up once I take off

[@naturalandsimplelife2131]

​@markrob9752 hi man having same issue . Did you find what was the issue. ? TiA

[@robertgoodwin777]

How much should the alternator read on the volt meter when the truck is running?

[@DIYSEMI]

depends, newer alternators run a little lower voltage, and higher amperage. anywhere between like 13.7 and 14.1 is very normal

[@robertgoodwin777]

Thanks for the info!

[@radub3929]

@@DIYSEMI I got the same alternator, new battery, battery voltage 13.0 after a day of driving, alternator voltage 13.8 with the truck running, what might be the problem ?

[@DIYSEMI]

@@radub3929 I don't see a problem

[@TheSpeedyr6]

My alternator running at 14.4 is that bad overcharging alternator

[@Sloba1992]

I changed belt and now showing 13.5 it was 13.9 with old belt, same belt same part number? Should it increase back to 13.9 if I drive it?

[@jf-he7dd]

New belts are way tighter. Probably will go back up once the belt is worn in.

[@Sloba1992]

@@jf-he7dd it went up to 13.9, but I replaced alternator 2 weeks ago for new one it was charging only 12.0

[@jlsims1276]

I’m having an electrical surging issue. When I turn the truck of the surging stops lights and everything is normal. But when truck is on.. surging begins.. can you help? It’s driving me crazy!! Thanks. 2012 Mack Pinnacle

[@DIYSEMI]

Is your voltage gauge surging high? How high is it going? Does it stay high? Or up and down?

[@DIYSEMI]

Sounds like a bad voltage regulator in the alternator. Will need replacement

[@jlsims1276]

Thank you!! Someone mentioned that today as a matter of fact! I appreciate it! Love your videos & to ad, I started my authority by watching you video on “authority”!

[@jlsims1276]

Hello DIY. In my 2012 Pinnacle. I’ve had my injectors changed about 3 weeks ago. But I’m starting to have “long start” issues now. My fuel/Water selector, keeps filling up to the to off the glass as well. What could that be?

[@DIYSEMI]

Likely separate issues. Had they checked the primer pump for leaks? As well as tested the fuel pump? Common issues with those

[@jlsims1276]

What are the two other wires?

[@DIYSEMI]

One is called remote sense...the other is for an indicator light in the dash...my truck has neither feature

[@jlsims1276]

I see. I’m having a surging issue and can’t figure it out..

[@jaytrutrucker]

I have a 60 series 14 liter I'm having voltage issue my voltage is going crazy going down to 12.5 then up to 15 volts

[@DIYSEMI]

Bad wire ..alternator..mine did that when my jumper wires between batteries went bad

[@AmirAli-hr5wy]

What is the problem if alternator charges more than normal

[@DIYSEMI]

To much voltage can cause damage in your electrical system....and your ecm

[@bvr1962]

you should not be wearing a ring, had a friend touched 24 volt possitive to the ground melted the ring and had to have finger amputated

[@DIYSEMI]

Yet another way being married is dangerous 😉😉. You are correct tho

[@elmavr]

I put new batteries and new alternator and still reads 12.3-12.8

[@DIYSEMI]

Try reading the voltage directly off the alternator. You could have some bad wires in between

[@tylerseabook9423]

I changed the alt and still 12.2 voltage

[@bobbycaldweld6332]

Did u find a fix yet im having the same problem

[@tylerseabook9423]

@@bobbycaldweld6332 yes wiring harness issue. Take it to the dealer. We’re a mobile repair company and we had to pull the pin

[@DIYSEMI]

sounds like you have a wiring issue. start by checking for loose connections.

[@dapper_gent]

12.4 volts??? Are you driving a Motorola??

[@LauraBruno33]

Good job. Wasn't hard at all...yah right lol

[@alexshortsplus]

He made it look easy...like your apple pies😄😄💕