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Doug
Doug, ASE Certified Technician
Category: Mitsubishi
Satisfied Customers: 8594
Experience:  Mitsubishi employed and Factory trained ASE certified technician
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New alternator, new battery. Battery light is still on

Customer Question

New alternator, new battery. Battery light is still on "solid" and the car charges at times and then quits charging.
JA: Lots of things can cause problems with the battery. The Mitsubishi Mechanic will know what to do. Tell me a bit more about what's going on so he can help you best.
Customer: It just charges at times and sometimes it don't, like the alternator is kicking in and then it don't.
JA: Are you hoping to fix this yourself?
Customer: Yes
JA: Great! What have you tried so far?
Customer: Replaced the alternator, battery, and relays.
JA: Is there anything else important you think the Mitsubishi Mechanic should know about your Mitsubishi?
Customer: I've also checked the fuses
JA: I'm sending you to a secure page on JustAnswer so you can place the $5 fully refundable deposit now. While you're filling out that form, I'll tell the Mitsubishi Mechanic about your situation and connect you two.
Submitted: 1 year ago.
Category: Mitsubishi
Expert:  Doug replied 1 year ago.

Hi,

What year make and model is this?

Customer: replied 1 year ago.
2004 Mitsubishi galant Es 2.4
Expert:  Doug replied 1 year ago.

Thanks.

Was this a genuine Mitsubishi alternator that was installed or was out purchased from an auto parts store? This is incredibly important, as these vehicle does not get along with aftermarket alternators. Specifically, the voltage regulators they use are common to burn out the external regulator in the pcm.

Customer: replied 1 year ago.
It came from advance auto parts its got a life time warranty
Customer: replied 1 year ago.
I've check ever thing
Customer: replied 1 year ago.
It will charge one min then it will stop charging it was the same way with the old one that I took off of it
Expert:  Doug replied 1 year ago.

Well this is the problem with these aftermarket alternators... The voltage regulators are not set up properly for external regulation. There is a reason that was the very first thing I asked... A lifetime warranty is great and all, but not if you can't even get one that works you know?

Customer: replied 1 year ago.
It is something electrical
Expert:  Doug replied 1 year ago.

Was the regulation circuit even tested before replacement, or the Allen mayor just changed as is?

Expert:  Doug replied 1 year ago.

Sorry the spell check is having a fun time with me today. That should have said or was the alternator just changed as is.

Customer: replied 1 year ago.
I just bought a new one so as is. Other than what you are saying could they be any other problem?
Expert:  Doug replied 1 year ago.

Well yes, it is possible the original alternator was fine and that the regulator inside the pcm failed. Whike not super common out does happen... Unfortunately it usually happens as a result of having one of these aftermarket alternators installed, meaning sometimes you'll find that you have an alternator failure, you put a cheap replacement on, and now you have an alternator and pcm failure to deal with. For the vast majority of issues though, you simply need to get the property factory alternator installed. These cheap Chinese regulators they use in the aftermarket ones simply can not be trusted.

Customer: replied 1 year ago.
Ok thank
Customer: replied 1 year ago.
Thanks
Customer: replied 1 year ago.
what is the pcm
Expert:  Doug replied 1 year ago.

You're welcome. Make sure all your connections are right of course, and if so get a factory unit on there and see where you stand... 99% odds you'll be fine after that. These get towed in to me from other shops all the time like this and it is nearly always just a cheap alternator at fault.

If the problem persists then we would have to consider a possible pcm issue, but we can't even test that without the factory design alternator installed (test results are useless with the aftermarket style regulators). Luckily it is pretty rare to go beyond just being the right alternator.

Expert:  Doug replied 1 year ago.

The pcm is the computer that runs the engine... It also controls the regulator inside the alternator. This is worst case scenario though, you definitely do not want it to be that as the pcm is not only wire expensive, it requires dealer programming as well so you can't just get a used one and their it in etc.

Expert:  Doug replied 1 year ago.

That should have said "very expensive". Not wire... Sorry the spell check is a little glitchy today

Customer: replied 1 year ago.
I was thanking about geting a new computer thanks for letting me know that if it comes to that I have to take it to a dealer right
Expert:  Doug replied 1 year ago.

You're welcome. Again luckily it rarely gets to that point, the factory alternator is usually all you need.

Expert:  Doug replied 1 year ago.

If I can do anything else for you just let me know.