alternator wiring diagram?

Disconnect the alternator wiring harness and check for power at the light green and red wire do you have it? Below is your charging system wiring diagram.

Disconnect the one with the light green and red wire-you check at the harness end.

Possible alternator ready to fry up and bomb out on you.
If you have Advance Auto Parts near you...have them check your alternator... They will check it at no cost.
Good Luck;
Rick

I have a 1990 lincoln town car with a 5.0L engine when i start up the car after a quater mile the dashboard lights go out the radio shuts off the heat shuts off blinkers don;t work nothing works but the car still runs when i shut the car off it won't start i'll jump the car and it starts right up could it be the altnator or voltage regulator is the regulator in with the altnator i need help fast i hope you can help me please thanks.

Hi sjpd1959,

Thank you for the donation.

You need to perform a test on the charging system to verify if it is a fault with the alternator.

A faulty ignition switch or power interruption can also cause the symptoms described.

1990 Lincoln Town Car

Digital cluster readout too dim in daylight. Do I neeed a cluster or could it be the voltage regulator?

Most likely the cluster or the dimmer for the cluster.Remove the dimmer and use a test light to see if the feed wire changes when you dim or brighten it, if nothing the dimmer may be bad, if it works but dash stays dim th ecluster may need to be repaired or replaced

Electrical problem
1990 Lincoln Town Car V8 Automatic

Hi,
I have a 1990 Lincoln Town Car and the alternator isn't working. I've checked on Fordparts.com for the replacement part and was narrowed down to three options.

1. 65 amp with 65.4mm grooves
2. 65 amp with 50mm grooves
3. 85 amp

I'm not sure which one is the one I should buy to install. I bought the car used and the one currently installed on the car has no specs details on it.

We can't tell you what alternator you have on your car but I can tell you as far as the first 2 go, you should be able to just swap pulleys to correct any problem there.

Amp light came on, Replaced Alternator, Batt. died two days later, replaced Batt. Batt. died 2 days later again, took off new alt. and checked it. Checked out ok, but still not charging, Is there a in line fuse somewhere!!! HELP

Hi towny. Welcome to the forum. I think I can help you but I have to search for a service manual. Electrical is my specialty, and my sub-specialty is charging systems. Until I find a book, can you describe the generator? Does it have a rectangular plug on the side with two very fat black wires with orange stripes? Or does it have the voltage regulator bolted to the back with a white, yellow, and green / red wire?

caradiodoc

Yes it has a rectanglar Plug with the two black wires with orange stripes, the other plug is a built in regulator?

Well, I found a book but the diagrams are really confusing. Can you tell me if your generator has an external fan on the front that you can push on with your thumb? Next, I think you have the 65 amp generator with the regulator bolted to the back. There's a three-wire plug on the regulator, with yellow / white, white / black, and light green / red wires.

If you have only a total of three wires, (black / orange, white / black, and orange / light blue), you have the 100 amp generator with an external voltage regulator. Since you have the more common dual black / orange wires, I'm using the 65 amp diagram.

Start by checking for voltage on the two black / orange wires. They should both have full battery voltage all the time. By the way. Those wires are never supposed to be unplugged because that will degrade the solid mechanical connection, and that will lead to overheating of the terminals and rapid failure. Replacement units come with a new plug already installed, and you are supposed to splice and solder the wires to the vehicle's harness. Weird, huh?

Next, the yellow / white wire in the regulator plug must also have battery voltage all the time. If it is missing, there is a fusible link attached to the starter relay. The wire has nothing in common with the starter circuit. It is just used as a convenient tie point. Of the six wires shown on that terminal, the fuse link is a gray 16 gauge wire. That is the weak link in the chain. The wire is smaller diameter than the main yellow / white wire so that's where it will burn open. The insulation is designed to not melt or burn. Test it by tugging on it. If it acts like a wire, it's ok. If it acts like a rubber band, it's burned open. You can buy replacement fuse link wire from the auto parts stores according to color. You can usually use less than half of the piece they give you so you'll have enough for another repair later.

Next, measure the voltage on the green / red wire. There should be 0 volts with the ignition switch off, less than about 1.5 volts with the switch on, (that terminal is grounding the dash light), and it should pop up to near battery voltage when the system is working. Battery voltage on both sides of the dash light turns it off.

Also, when the system is charging, there will be around 5 - 7 volts on the white / black wire. That voltage is tapped off the output and is what tells the voltage regulator to raise the voltage on the green / red wire to turn off the warning light.

Let me know what you find on those wires.

caradiodoc

All fixed, I found a broken wire in the harnessjust off the alternator THANKS

Initially ,charging light came on, change to interstate battery, re-manufactured alternator from advance auto,replaced positive cable leading from battery to solenoid, replaced negative battery cable leads to ground,(ground is to engine and body). I am at a dead end. Now the charging lamp flasher, also get a check engine light. Suggestions please.

check all the fusible links in picture one or all of them can be blown they will be on starter relay or where positive battery cable hooks up for check engine light, scan for codes. get code get back to us with code. connector is under hood.

The "Charge System" warning message appeared on the message center. I assumed this was the alternator failing. I connected a battery charger and found the battery to be holding charge and 12.6 volts at rest. I bought an alternator from my local pep boys and installed. No difference - message still appeared and Batt not charging. Didn't realize but the 100 amp alternator has an external voltage regulator. Found one at my local Auto Zone replaced it. Still nothing - message and no battery charge continues. What do I do next?

Look for a blown blue 15 amp fuse. Next, measure the voltages on all of the wires while the engine is running, then holler back with those numbers.

12.1at batt and batt connection at alternator, at plug in connector the front wire (field possibly) 0.1 volts, rear wire (stator?) 0 volts, at regulator: I connection 0.9 volts, A connection 12.1 volts, S connection 0 volts, F connection 0.1 volts. No blown fuses

Do you have wire colors to go with the voltages?

12.1 at the battery wire is correct. If there's 0 volts at the stator (white or white / black), that means there's no output. That tells the regulator to turn on the battery warning light. "A" is system voltage sensing and should be 12.1 volts. The field should be higher. The higher the voltage, the higher the current flow through the brushes and field winding. The higher the current flow, the bigger electromagnet it makes. The bigger the magnet, the more output current you'll get. With 0 volts on the field, there won't be any output generated.

When you measure these voltages, measure at the generator and at the regulator to be sure you have the same voltage on each end of each wire. If one has different voltages, look for a corroded wire or a loose terminal in a connector.

Be sure the voltage regulator is bolted solidly to the body too. It needs a good ground to work.

what does the I terminal (green with red stripe) of the regulator do? With ignition switch in run and nearby connector disconnected, the green w/red stripe wire has 11.7 volts (battery at 12.1). Reconnect the regulator and it drops to zero volts! Also it was red with blue stripe that has 0.1 volts while car runs and white with blk that is zero volts.

Sorry to leave you hanging. Have you solved the problem yet? The green / red wire provides the turn-on signal for the voltage regulator. With the plug disconnected you'll be reading the 12 volts that comes through the ignition switch and dash warning light, (or a resistor that replaces that light on some cars). It went to near 0 volts when plugged in because the regulator was grounding that wire to turn on the warning light. When the system is working about 6 volts appears on the white / black wire to tell the regulator to turn the warning light off. THAT'S when you should again find full battery voltage on the green / red wire.

Look for a yellow wire in the connector. It should have full battery voltage all the time. If it doesn't, a fuse or fuse link wire is blown.

That connector is part of the voltage regulator. It's held on with four small bolts in a rectangular pattern. If you can see back there, you'll find two additional bolts. One might be covered with a plastic cap. The other one has printing stamped next to it that says "Ground here to test". Use a piece of wire to ground that bolt while the engine is running. If the headlights get brighter and the system voltage goes up, the regulator is defective and can be replaced separately. If there's no change in system voltage, further tests will determine the cause but worn brushes are the most common thing to find. They come as part of a new voltage regulator. I can walk you through the testing procedure. You'll need an ohm meter or test light.

Electrical problem
1989 Lincoln Town Car Automatic

WITH GOOD BATTERY CHARGED THE CAR STARTS AND RUNS FOR 1/2 HOUR THEN DIES. ALTERNATOR AND BATTERY TESTED GOOD. WHEN RUNNING IF YOU DISCONNECT THE BATTERY CABLE IT DIES??

The charging system is not working and you need to determine why.

Hey thanks for getting back, the problem continues. I work retail, getting time away from my store is hard this time of the year. The regulator is external of the alternator, mounted on the wheel well. I don't see anything that says ground to test... I will check yellow wire this afternoon. Thanks again!

that is what we are trying to figure out. any ideas of where in the charging system?? where else should we look??

There's two different generators for your car. I got sidetracked searching for a diagram with the correct wire colors on the external regulator version. For now, jumping between the "I" and "F" terminals on the regulator will bypass it and "full-field" the generator. Those should be the first and fourth terminals. That will make it charge wide open if the regulator is at fault. Don't raise engine speed and definitely don't disconnect the battery when doing the full-field test. Either of those things will allow system voltage to rise to dangerous levels if the generator is working.

If bypassing the regulator makes the generator work, you'll see the head lights get noticeably brighter, or, if you're monitoring battery voltage with a digital voltmeter, you'll see the voltage go up to around 14 to 16 volts at idle. That will prove everything other than the regulator is working.

If bypassing the regulator causes no change in output voltage, the problem is in the generator or wiring. I can walk you through that diagnosis once I find a diagram.

AGGHHH!! Do not disconnect the battery with the engine running! That was a poor man's trick done many years ago by mechanics who didn't understand how charging systems worked or how to diagnose them. The battery is a key component in regulating system voltage. You are lucky your generator isn't working. If it was, and you raised engine speed, it is possible for the output to go to over 30 volts. Computers can not tolerate that kind of voltage and the voltage spikes that are normally dampened by the battery. While a 1989 model might not suffer irreparable harm, newer cars can have up to 47 computer modules. If enough of them are damaged, the car may be not worth repair.

The place to start is by measuring battery voltage with the engine running. You must find between 13.75 and 14.75 volts. Based on the symptoms, expect to see less than 12.6 volts verifying the dead charging system. How was your generator tested? Also, can you describe the connectors on it? Do you have a plug on the side with two fat black wires with orange stripes, or do you have a single fat black wire bolted to a terminal on the back?

caradiodoc

Apparently there is a wiring modification for the alternator on this car. Ask your friendly parts supplier.

My AMP light came on the other day, so I connected my voltmeter to the battery which revealed 12.6 volts with the engine off. I then started the car and the voltmeter revealed 12.5 volts. I increased engine RPM to 2000 and the voltmeter still read 12.5 volts.

I removed the alternator belt, disconnected the negative battery terminal and gave the alternator pulley a spin...it spun freely. I then reconnected the negative battery terminal and the pulley spun, but not as freely as with the negative battery terminal disconnected. The pulley also does not spin freely when the ignition is in the 'ON" position. I once read that if the pulley spins freely with the key in the 'on' position, then it's either a faulty voltage regulator or the alternator brushes need replaced.

This is a 2G ( 2nd generation ) alternator. The voltage regulator is attached to the rear of the alternator & the brush holder is attached to the voltage regulator.

Could you tell me if this is could possibly be a faulty voltage regulator, or is it most likely a diode or stator issue? Should I replace the alternator?

Thank you

you really need to check output of alternator first which autoparts do for free. but also check if the fusiblelinks are any good that may be the reason as well.

THE EZist THING TO DO IS SNATCH "MR. ALTERNATOR" OFF AND HAVE A POPULAR AUTO PARTS STORE BENCH TEST IT

IF IT TESTS BAD, THAT'S PROBABLY THE WHOLE PROBLEM

IF IT TESTS GOOD, THEN YOU MIGHT NEED TO DIG DEEPER INTO CONNECTIONS/ FUSIBLE LINKS/ BROKEN WIRES AND OF COURSE, YOU HAVE ALREADY LOOKED AT THE FUSES!

IN READING WHAT YOU HAVE ALREADY DONE, I DID NOT DETECT THAT YOU SNATCHED THE BATTERY CABLES OFF WHILE THE VEHICLE WAS RUNNING. THIS WAS A TRICK FROM THE '70s ON BACK. YOU CAN REALLY DAMAGE SOME STUFF DOING IT NOW-A-DAYS!

THE MEDIC

my alternator on my 1988 lincoln town car keeps blowing. i replaced the elcetrial unit behind the dash that shows the clock and the flashing charging system at the advice fo my local dealer. but still blows the alternator out. what else could it be?
help :(

Are you sure that your purchasing the correct amperage alternator. If you try to buy one that isn't capable of supplying the needs of the vehicle your esult will occur. Try buying a new alternator not reman. it's usually the voltage regulator that goes anyway.

Have replaced altentor,solnoid,starter.Was able to get car started.Charge System light still flashes. Battery was checked (12 plus volts). Battery hot terminal was getting hot untill i replacet starter.

Charge System light still flashes. Load test the alternator and double check connection at alternator and battery.

A good battery should be 12.8 volts when load tested should hold 9.6 volts in 10secs if not it needs replacement.