2005 XLT V8 Check Charging System

Ok.. my battery light came on.. alt was dead not charging.. I replaced the alt. all voltages are good. but the message center keeps saying "check charging system" the two small wires in the connector are reading 12+ volts each and the red is reading 14+ and i am getting 14volts at the battery now as well.. but light stays on in side truck???

The following might be read only if you have made replacement to non-original alternator.
I think you have incorrenct inetrnal resistance of voltage regulator of your new alternator.
Alternator connected to PCM by A-S-I scheme.
A is connected to battery "+" terminal.
S is connected to alternator internals and used to direct voltage regulation. Its about 8-10V while alternator operative.
I is connected to PCM and used to startup and control the alternator.
When engine is off, line I has 0V voltage.
After normal engine start PCM will enable alternator by sending signal to alternator using line I. On the other hand, PCM controls how much voltage dropped on alternator by line I. It must be about 8-10V. If the voltage drop less than 8V or greater than 10V, so PCM will send command to instrumental pabel to light 'check charngin system message'.

The correction can be maid two ways:
1. Expensive way - replace alternator to orinal spare.
2. 'Kolkhoz' way - using multimeter, measure the alternator line I voltage drop, calculate neccessary addinitional parallel resistance to make target 8-10V, Connect line I to ground via neccesary resistor, enjoy. ;-)

Humm.. my 2005 has only two wires on the connector and the B+ the red 8gauge wire going to the batt.. unless i'm missing something

It's not a problem: there was two connection schemes in 2004/2005: more modern ASI and earlier AI-connection. You have the second one. All I wrote above is applicable to the AI-connection as far as to ASI-type.

As it wrote in wiring diagram for Ford Explorer, "A"-connection is OG/LB color, "I" connection is LG/RD color.
Use thin pin and multimeter to measure voltage drop on I circuit (between I and ground, when engine started). Next, will think what to do with results. ;-)

And of course, before thinking of above, make sure (when engine started) you have enough voltage (13.3-15V) on battery terminals under some load (all headlights and foglamps on, heater fullspeed, rear window defroster on) when idling and at 2000 engine rpm. Your alternator working?

another suggestion. . .when my alt went out ('04) the auto parts store had two type of replacements one was 'Black Rear Cover' or non-black rear cover (silver). The Book couldn't differentiate between the two, i had to bring in the alt and made sure they looked exactly the same. Black Rear cover was an overnight part they didn't stock it. First install was a reman.

then 6 months later, of course on a 4 hour trip the 'Check Charging' light turned on, i thought here we go again, . . . on/off the rest of the trip. It appeared to be charging but the PCM didn't think so. When we got i back it was returned under warranty and for $30 more i exchanged it for a new one. No problems since. Not sure if you got a reman, but they can be hit or miss if they work and last.

Yes I have the one with the black cover on the back. I'm gonna have them check it on there machine.. RATS!!

jrford said:

When we got i back it was returned under warranty and for $30 more i exchanged it for a new one. No problems since.

Click to expand...

The main idea.
Of course, if you have possibility to return under warranty - do it immediately

Remans have not been that good as of late... Get another one!

Update.. 2005 Explorer V8 XLT Battery light on and The "CHECK CHARGING SYSTEM" on the message center was on after using a refurb from Auto Zone
....
AutoZone alt. was returned,, I was getting a full charge, but i don't think it was talking back to the truck to turn the the battery light off in the truck even though everything else was working, meaning 14volts and charging.. got a full refund..
took that money to the Ford dealer and got one from them..
Part # F8OZ-10V346-CARM This one had a 3 terminal connection I believe the AZ one only had a 2 terminal connection, even though the cable from the truck had only two wires the green and orange one.. The middle connection was not being used i guess.. any way all is well..

Got 14 Volts on the B+
Got 14 Volts on the Batt terminals
The "CHECK CHARGING SYSTEM" on the message center is off
The Battery Light is off as well..