Before we get started I would like to point out a few things..
My 2003 XLT 4.6L is running great, I installed a 7000 Watt audio system about 6 months ago and the lights Dimming issue was expected so next step was to upgrade the alternator..
Ordered a Large Case 370a CES Alternator built especially for my vehicle..
As CES suggested a minimum of a 1/2 shorter belt is recommended so I went a bit further and replaced the Belt Tensioner and all 3 Idler drive align pulleys while I was at it..
next would be a couple extra battery.. Well, I've not made it to the Battery upgrade..
When I install New Alternator the battery light comes on and battery voltage drops from 12.6v to 11.9v
It pretty clear it's not charging and unplugging the pigtail from the alternator has no effect on the system.. I can put the old alternator back on and everything goes back to working great..
New Alternator is in A+ running condition(Had it tested at 2 different locations), All wiring, Fuses, Pigtails, Voltage drops and relays have been tested and all are A+..
All is good and nothing is bad so my question is..
Is there a workaround to get the PCM to tell the alternator to charge which is what I think the problem is
Pretty sure someone has had this issue so any help would be appreciated..
My 2003 XLT 4.6L is running great, I installed a 7000 Watt audio system about 6 months ago and the lights Dimming issue was expected so next step was to upgrade the alternator..
Ordered a Large Case 370a CES Alternator built especially for my vehicle..
As CES suggested a minimum of a 1/2 shorter belt is recommended so I went a bit further and replaced the Belt Tensioner and all 3 Idler drive align pulleys while I was at it..
next would be a couple extra battery.. Well, I've not made it to the Battery upgrade..
When I install New Alternator the battery light comes on and battery voltage drops from 12.6v to 11.9v
It pretty clear it's not charging and unplugging the pigtail from the alternator has no effect on the system.. I can put the old alternator back on and everything goes back to working great..
New Alternator is in A+ running condition(Had it tested at 2 different locations), All wiring, Fuses, Pigtails, Voltage drops and relays have been tested and all are A+..
All is good and nothing is bad so my question is..
Is there a workaround to get the PCM to tell the alternator to charge which is what I think the problem is
Pretty sure someone has had this issue so any help would be appreciated..
Last edited: