Wiring Diagram 2000 Ford Taurus Charging Circut
Joined
·
22 Posts
Discussion Starter · #1 ·
I have replaced the Alternator and drive belt and it is still not charging. I the new alternator bench tests ok at Advance Auto but when it is in the car their diagnostic machine reports no voltage from alternator. All fuses are good. The Battery light on the dash does not light at all, even when all the other lights are illuminated for testing before starting the car. The wiring diagram I have in the haynes manual indicates that this light is on a 5amp fuse in position #11. I have battery voltage on the large output cable on the alternator and the first wire on the three wire connector to the alternator.
Joined
·
4,352 Posts
The Battery light on the dash does not light at all, even when all the other lights are illuminated for testing before starting the car
The battery bulb is probably burnt out.
How do you know that it is not charging?
Joined
·
52 Posts
I have replaced the Alternator and drive belt and it is still not charging. I the new alternator bench tests ok at Advance Auto but when it is in the car their diagnostic machine reports no voltage from alternator. All fuses are good. The Battery light on the dash does not light at all, even when all the other lights are illuminated for testing before starting the car. The wiring diagram I have in the haynes manual indicates that this light is on a 5amp fuse in position #11. I have battery voltage on the large output cable on the alternator and the first wire on the three wire connector to the alternator.
You have to be careful here, there are several 6G alternators available identified by the regulator color. At least two are under computer control for load and have no direct connection to the battery light.
DuBois Marketing, Inc.
Do not take the years literally, my 2003 had a white/grey regulator. Was a PITA and burned the first replacement.
Do not neglect to check the megafuse.
Joined
·
22 Posts
Discussion Starter · #4 ·
Poppy the battery voltage is below 12 volts with the car running. With a load - lights, AC, Fans, Etc on it is below 10 volts. The speedo goes to zero and the ABS and orange SRS lights light dimmly and the car has stopped running. I have charged the battery completely several times and it has test good at Advance Auto.
Joined
·
22 Posts
Discussion Starter · #5 ·
The battery bulb is probably burnt out.
The car only has 250,000 miles on it. That is what I thought but did not know if it maybe related to the alternator not charging. The clips that hold the radio in are broken so I have not been able to remove the radio assembly with the quick release tool to check the bulbs in the IP (Instrument Panel). That is the first step listed in the Manual for replacing IP bulbs.
Joined
·
22 Posts
Discussion Starter · #6 · (Edited)
You have to be careful here, there are several 6G alternators available identified by the regulator color. At least two are under computer control for load and have no direct connection to the battery light.
Was a PITA and burned the first replacement.
Do not neglect to check the megafuse.
The megafuse has the same voltage on both sides. If the Megafuse were blown would not all the power to everything be gone??
Joined
·
4,352 Posts
See if this helps
Joined
·
22 Posts
Discussion Starter · #8 ·
Poppy, Yes this looks like the diagram in the Hayes Manual but does have more detail IE: wire gauge and connector pin numbers that maybe helpful. There are actually 4 wires connected to my alternator, three in the connector to the regulator and the large (6 AWG??) output cable.
Joined
·
22 Posts
Discussion Starter · #9 ·
This appears to be the closest wiring for my alternator. It does have a white connector to the regulator.
-
11.3 KB Views: 37,625
Joined
·
52 Posts
Keep in mind that the ECU controls the charging voltage.
The terminals are:
AS (A) - Voltage sensing
RC (SIG) - Pulse width modulated signal sent to alternator to vary alternator output voltage.
LI (I) (FR) - Alternator load info sent to ECU. This is used to reduce alternator load when engine load is high.
Signals are pull-down. If the connector is unplugged and you check the RC terminal on the alternator with an oscilloscope you will get DC. The connector side RC terminal will be ground. When the connector is in you will get a square wave that changes duty-cycle as the ECU changes demand. This is because the ECU output transistor can only ground the signal wire when it wants the signal to be low, when the signal should be high the output transistor turns off and the alternator end of the wire supplies the voltage. You can use this for diagnosis by supplying the voltage through a resistor to the RC terminal of the plug and taking the alternator out of the loop to check the ECU signal.
The reverse is true of the LI. The ECU supplies the volatge and the alternator pulls it down to modulate the output.
Joined
·
22 Posts
Discussion Starter · #11 ·
Signals are pull-down. If the connector is unplugged and you check the RC terminal on the alternator with an oscilloscope you will get DC. QUOTE]
I do not have an oscilloscope. I could follow only some of you explanation. What size resistor should be used on the [RC] terminal and should it go to ground?
Joined
·
52 Posts
I do not have an oscilloscope. I could follow only some of you explanation.
You cannot check the signals without an oscilloscope. The use of a 1000 ohm resistor will prevent system damage.
Again, there are several versions of incompatible 6G alternators.
You need the original alternator numbers or regulator type to properly identify it for replacement.
Buying an alternator based on car model and year info does not guarantee you will get the correct one.
If you no longer have the original alternator and you know what you are doing, a little testing with a scope could point you in the right direction. If done incorrectly you can damage the ECU or wiring.
At the least find out what type they sold you as a replacement and try another type.
Joined
·
338 Posts
Ok im just gona throw this out there ... because im tired and dont want to read thru all but look for a lose guage wire around the sylinod area. old schools fords had to have to wired to use the charging system ... dont know why an old timmer told me that and he was right almost always, maybe the same applies, if it not lighting you may have a problem with the wire and some how it not charging ... maybe this will help maybe not
Joined
·
22 Posts
Discussion Starter · #14 ·
Well I finally took the car to the shop. It appears it was the wire to the dash light which also supplies 12 volt to the alternator. The light still does not work because they did not trace the complete circuit and just pulled 12v from the fuse block under the hood. Does anyone know how to mark this thread as resolved?
Joined
·
4,352 Posts
Any moderator can mark it resolved, and open and close a thread.
Periodically we close all resolved threads.
So that we don't get a lot of me too's on old threads
Posted by: modellinnow.blogspot.com
Source: https://www.fordforumsonline.com/threads/2000-taurus-is-not-charging-the-battery.2369/