420A 95 eclipse alternator not charging battery need help asap

[Mc330]

I got a 95 eclipse gs N/T replaced the alternator thinking it was that but still wasn’t charging battery took the old alternator up to auto zone and it read fine checked the fuse it was good and the alternator to battery wire was good I don’t know what to do could it be the voltage regulator if so where is it located? Or a short somewhere and how do I check it

 

[Spideydsm99]

Battery is shot then, if the alternator is working and the battery isn’t keeping a charge then yeah it’s a bad battery. The regulator is built into the alternator btw.

 

[Mc330]

Battery was checked too and was still good

 

[Spideydsm99]

How’s the battery ground?

 

[mitsubishikid]

did you test the alternator fuse yet? looking at it is not good enough to cross it off the list use a multimeter, also inspect the + charge wire make sure it is not corroded and as mentioned above do the same for the - ground wire, also inspect the wires on the alternator connector maybe one of them is burned out so the alternator is not being triggered when the car is in the on position. these diagrams might help you.

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[Mc330]

I made sure I tightened the ground real good and checked the atl. Fuse with a multimeter and it was good

 

[Spideydsm99]

Yeah but is it clean?

 

[Spideydsm99]

How did you test the alternator charge wire?

 

[Mc330]

My mechanic said he checked every wire and the only thing it could be is the voltage regulator but idk where it’s located

 

[Spideydsm99]

Like I said it’s built into the alternator.

 

[Spideydsm99]

Have you checked the relay?

 

[Mc330]

Nope how do I check it and where is it

 

[Spideydsm99]

Nvm I forgot they don’t have a relay. Haha but if you have a volt meter jump it and test the wires coming from the alternator.

 

[Mc330]

Just checked the wire coming from atl to fuse again and wasn’t putting barely anything out

 

[Spideydsm99]

What was it putting out? And make sure the plug on the alternator is pushed all the way on.

 

[Mc330]

12 volts from battery

 

[Spideydsm99]

With the car running or off?

 

[Mc330]

Running

 

[Spideydsm99]

Check the plug. If the alternator isn’t seeing a draw then it will not charge the battery.

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[Mc330]

Checked that too only thing left is the ecu where the voltage regulator is

 

[Spideydsm99]

Yeah I forgot the 420a has regulator in the ecu.

 

[Mc330]

Just ordered a new ecu hopefully it works out

 

[Spideydsm99]

Let us know!

 

[Mc330]

Put in the ecu now the fuel pump won’t kick on

 

[mitsubishikid]

A lot of newer Chrysler cars had the regulator control built into the ecu, if this is the case, you can wire in an external voltage regulator, for a lot less then the cost of a brand new ecu, return the ecu from wherever you got it, and then get a voltage regulator and wire pigtail for it from a 1985 dodge d150 pickup and then wire it up, like in the video below, and you should be set. it makes a lot of sense to do it this way because buying another ecu every-time this happens can drain your wallet .

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I wired this setup into my Mirage back when I was running the 4G15 motor and wanted to use a larger amp alternator that had no internal regulator, and I had no issues with it.