Baffling charging system issue

hyundai
elantra

#1

I have a 2004 hyundia elantra that keeps running of the battery
Aternator sent to the rebuild shop…they tested it good.
They tore it down and found no issues…
The postive battery cable has 0.2 ohm continuity from end to end
The body of the alternator shows .1 ohms to battery ground
The two wires in the alternator connector shows 12 volts when key is turned on.
Belts are new and tight.

This did not happen all at once…was intermittent for days…now completly not charching…

What am i missing


#2

Your battery is weak and not holding a charge.Replace it


#3

Check if the fusible link BATT 120 amp is blown.

It’s located in the engine compartment relay/fuse block.

Tester


#4

New battery …the engine is running off the battery so it not a weak battery issue…the issue is the alternator is not charging even though all seems right.


#5

That fuse is good…plus it would have to be for the engine to run off the battery …right?


#6

There are 3 wires, the white wire/cable is the charge circuit, should have battery voltage with the ignition off or on.
The red with also has battery voltage at all times.
The blue/orange wire has power with the ignition on.


#7

I had a similar problem once before, it was the brushes in the alternator.

What was happening was the brush’s were wore out and bumping the alternator would get the brush’s to make contact just long enough to test good, shut the car off and they would lose contact and had to tap the alternator next time I started the car to get it to charge.


#8

You can’t measure the resistance of a thick cable with an ohmmeter. The 0.1 and 0.2 Ω readings are essentially zero within the accuracy of the ohmmeter.

Your best bet is voltage measurements. What do you read on the battery when engine is off? should be about 12.6 volts if the battery is charged. Much less than that and the battery is discharged or dead.

When the engine is running, it should go up to 13.4 to 14.5 volts. If not, the alternator is dead.

Did you take off the battery cables and check the connections for corrosion, inside and out? both ends?