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Last week, my Mark VII started dying and tests showed it was getting nothing from the alternator. I replaced the alternator and the regulator. Once it is jumped, it will run for about 10 minutes then die again. Where should I look next?

Submitted: 441 days and 9 hours ago.

Category: Ford

Value: $9

Status: AWAITING CUSTOMER ACTION

1992 Lincoln Mark VII 5.0-HO

Already Tried:
Replaced the alternator and the regulator.

Posted by Brian 441 days and 9 hours ago.

Info Request

Have you checked voltage at the battery while the engine is:

being started
running
engine off?
Did you charge the battery before replacing the alternator?

441 days and 9 hours ago.

Reply

We checked the voltage at the battery while it was being run. It was getting nothing from the alternator. So, I replaced both the alternator and the regulator. I then had the car jumped and let it run to recharge the battery (which is new). About 10 minutes later, the car died again.

Posted by Brian 441 days and 9 hours ago.

Info Request

Did the voltage get checked after the new alternator was installed?
Does the car re-start after dying?

441 days and 9 hours ago.

Reply

No, I don't have the equipment here to do it. The car will not restart after dying because the battery is drained. You should know that the car has onlyh 43000 miles on it and sat unstarted for the past 1.5 years until I got the car a month ago. Everything ran fine until last week. Would a fusible link issue cause the problem?

441 days and 9 hours ago.

Reply

One other thing I forgot to tell you. The problem started less than a day after I installed a new stereo system. I pulled the system immediately after the problems started, but they continued.

Accepted Answer

Yes it could be due to fusible link. The fat black/orange wire from the alternator to the battery has a fusible link that could have been blown if someone tried to replace the alternator without disconnecting the battery, or if the fat wire somehow shorted to ground.

If the fusible link blew, it would make the alternator unable to charge the battery. Did you notice the battery indicator on in the cluster while it was running?

I would recommend getting a cheap digital multimeter from Wal-Mart or Harbor Freight, or borrow one, we need to see if the alternator is charging. With the engine running, a charged battery, and a working alternator, the voltage should be somewhere between 13-15 volts. With the engine off, a fully charged battery should show 12.6v. I think the alternator is not charging, probably due to a wiring problem since it is a new alternator.

The light green/red wire at the alternator is the trigger that turns on the alternator when it gets 12 volts from the battery charge indicator bulb in the cluster, when the key is in RUN. You can verify whether the voltage is present on this wire at the alt with a voltmeter. The yellow/white wire is a sensing circuit that the alternator uses to monitor battery voltage so it can determine the appropriate output voltage. The yellow/white wire also has a fusible link that can blow.

Be careful about letting the alternator charge up the battery from a low charge, that can put a lot of stress on an alternator. If you have a battery charger, let that handle the recharging, or leave the battery connected to another vehicle to be recharged.

I found the following wiring diagram, showing the alternator. It is for a 92 Mustang, but should be pretty similar:

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Accepts:
Expert:	Brian
Pos. Feedback:	100.0 %
Answered:	9/7/2008

Auto Service Technician

5 years Ford Technical Hotline/Service Engineer. 2005 Ford Master Cert. Automotive Technology degree

441 days and 8 hours ago.

Reply

Brian,

The diagram you sent might not be helpful because the Mark VII has separate alternator and regulator, not an integral one. Thanks for trying, though.

Steve

Posted by Brian 441 days and 7 hours ago.

Answer

The wiring will be arranged a bit differently, but the system still works basically the same way. The light green/red still works the same way, and the yellow/white as well. They should both be fusible link powered for safety. There will be some wires between the regulator and alternator that aren't shown, but you can do simple end to end checks, and check to make sure none of the wires are shorted together. The regulator gets turned on by the light green/red, an then it sends a variable amount of current through the orange/light blue wire to control the amount of output.

On an internal regulator alternator, there is no orange/light blue wire because the regulator has brushes that connect directly to the alternator's rotor slip rings.(The orange/light blue wire may be a different color, I am referring to a 1988 diagram, but they tend to keep the colors standard.) If you look where the wiring connects, you will see a the letters I, A, S, F on the regulator.
I = Initiation of the charging by the lt grn/red,
A = voltage sensing wire,
S = Stator monitor wire usually runs at 6 volts,
F = Field which is the power that energizes the field coil and determines the output.
The alternator may be marked F, S, and B+,
B+ is the fat black/orange wire that carries the current that charges the battery.

441 days and 7 hours ago.

Reply

thank you!!!!

Posted by Brian 441 days and 4 hours ago.

Answer

No problem, let me know how it works out.

441 days and 3 hours ago.

Reply

this was a continuation of the question answered and paid for because it had to do with the diagram provided. if I "accept," do I pay again? I really don't have the money to pay twice for the same answer. I paid $15 already, and Brian was VERY helpful.

Posted by Brian 441 days and 3 hours ago.

Answer

No you don't have to pay again.

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Question

Last week, my Mark VII started dying and tests showed it was getting nothing from the alternator. I replaced the alternator and the regulator. Once it is jumped, it will run for about 10 minutes then die again. Where should I look next?

Optional Information

1992 Lincoln Mark VII 5.0-HO Already Tried: Replaced the alternator and the regulator.

Info Request

Have you checked voltage at the battery while the engine is:being startedrunningengine off?Did you charge the battery before replacing the alternator?

Reply

We checked the voltage at the battery while it was being run. It was getting nothing from the alternator. So, I replaced both the alternator and the regulator. I then had the car jumped and let it run to recharge the battery (which is new). About 10 minutes later, the car died again.

Info Request

Did the voltage get checked after the new alternator was installed? Does the car re-start after dying?

Reply

Reply

One other thing I forgot to tell you. The problem started less than a day after I installed a new stereo system. I pulled the system immediately after the problems started, but they continued.

Accepted Answer

Reply

Brian, The diagram you sent might not be helpful because the Mark VII has separate alternator and regulator, not an integral one. Thanks for trying, though. Steve

Answer

Reply

thank you!!!!

Answer

No problem, let me know how it works out.

Reply

this was a continuation of the question answered and paid for because it had to do with the diagram provided. if I "accept," do I pay again? I really don't have the money to pay twice for the same answer. I paid $15 already, and Brian was VERY helpful.

Answer

No you don't have to pay again.

Related Ford Questions

1992 Lincoln Mark VII 5.0-HO

Already Tried:
Replaced the alternator and the regulator.

Have you checked voltage at the battery while the engine is:

being started
running
engine off?
Did you charge the battery before replacing the alternator?

Did the voltage get checked after the new alternator was installed?
Does the car re-start after dying?

Brian,

The diagram you sent might not be helpful because the Mark VII has separate alternator and regulator, not an integral one. Thanks for trying, though.

Steve