Battery Warning Light

[cw212010]

Hi all,

New battery, reman alternator - Everything in good condition, battery greased up, truck starts and runs fine, all connections appear as new, battery tested and no codes in the system yet I've got a red battery light and 'check charging system'.

Any ideas? This fault is displayed however there is no fault on a code reader....

 

[extra-medium]

have you tested the alternator to make sure it is good? You should be able to have it tested at autozone or advance auto depending on which one is located near you.

 

[NineFootNails]

A couple things....

Have you a voltmeter to check voltage while running? Should be around 14 volts.

Second, I have seen many new alternators fail when replaced as follows:

1. Battery dead, replace alternator.
2. Jump start truck and let new alternator charge dead battery.
3. Destroy new alternators voltage regulator by charging dead battery on maiden voyage.
4. Still have charging problems.
5. Replace battery.
6. Still have charging problems but have a new battery and new (bad) alternator.

Recommendation if you find battery voltage (~12.4volts) when running (should be ~14.0 volts) is to remove "new" alternator from vehicle and have it bench tested. If it tests good start checking wires for continuity and good grounds.

Here in MN cables can appear good but can corrode back in the jacket due to salt in winter. Using an ohm meter will help you determine if this is your issue.

As always, being an online diagnosis this information may not solve your problem but may help. Hope it does.

 

[cw212010]

The battery and alternator have been tested by AutoZone and no fault found - Can't explain why I still have a battery warning light/message on....

 

[Number4]

If you have an issue with the wire that goes from the alt. to the PCM, your battery light will come on.

Wiggle the connection and see if the light goes off.

Was the alt and battery tested in the car or off the car?

 

[TechGuru]

What brand alternator? Use nothing but Motorcraft or Bosch.

4.0L Bosch NEW AL7543N More Information for BOSCH AL7543N $124.79 130amp

4.0L Bosch Remanufactured AL7543X

4.6L Bosch NEW AL7541N

4.6L Bosch Remanufactured AL7541X

 

[Mattm6555]

Hi all,

New battery, reman alternator - Everything in good condition, battery greased up, truck starts and runs fine, all connections appear as new, battery tested and no codes in the system yet I've got a red battery light and 'check charging system'.

Any ideas? This fault is displayed however there is no fault on a code reader....

So I figured it out finally now that its warm and I could take my time and work outside without the bitterness The harness was crimp to tight on the driver side under battery where the bracket that holds it back from the belt and **** through the plastic rubed the green with red line voltage regulator wire bare and frayed just a less than a 16th of an inch split from that bracket being crushed over the harness to hold it yup as it would have that minimum amount of shake from the road and motor it would lose and regain connection to the voltage regulator and is also the reason my 4x4 control module is fried from the power spikes that it caused had to disconnect battery relay and fuse panel ac pump front driver and side by the battery grounds take the wheel well out get the bracket off and un hinged from the harness and pull harness into wheel well to look threw it thoroughly and then just jumped bad spot with a set of u-haul clips to jump the bad spot finally I have victory

Hope it helps