I’ve been noticing recently that my alternator warning light has been flickering when the car is idling. At speed the alternator warning light would go out. To me, this means that either the alternator is starting to fail or the load on the alternator exceeded the amount of current it could provide at idle. If low current at idle was the problem, adding air conditioning and electric assisted power steering only exacerbated the problem. To remedy either of these possibilities, the best course of action would be to replace the alternator with one that could provide enough current for all of the car’s upgraded systems. Rather than replacing the alternator with a stock replacement, I decided it was time for an upgrade that could provide both more current at lower RPMs as well as more total current output.

Each of these options had pros and cons.

Upgraded Direct bolt-in Replacement

Pros:

• Easiest install – no wiring changes
• Maintains original appearance
• Easy return to factory stock
• Maintains factory ammeter or alternator warning light

Cons:

• Lower current output at idle
• Few vendors – harder to find replacement while travelling

GM Style 1-Wire Alternator

Pros:

• Higher current ratings than 1G
• Eliminates external voltage regulator

Cons:

• Requires wiring changes
• Lower idle charging amps compared to the 3G
• Too high of an amperage could cause belt squeal
• Doesn’t support the alternator warning light or factory ammeter
• Might be more difficult to source a replacement while travelling

Ford 3G Alternator

Pros:

• Higher current ratings than 1G
• Eliminated external voltage regulator
• Higher idle and low-speed amp output
• Able to support factory alternator warning light (with wiring modifications)
• Uses an unmodified factory alternator – easier to find replacement while travelling

Cons:

• Requires wiring changes
• Too high of an amperage could cause belt squeal
• Doesn’t support the factory ammeter

All of the options would work. I chose the Ford 3G alternator for better idle current, easiest to find replacement, and ability to retain the charging warning light. I chose to use a kit from PA Performance to adapt the 3G alternator. While not strictly necessary, it made the conversion slightly easier.

These are the parts I used for the conversion

	Alternator – DB Electrical AFD0025 Alternator Compatible With/Replacement for Ford F600 F700 F800 F900 HD Truck 19901999, L6000 L7000 L8000 L9000 1989-1999, B600 B700 B800 Heavy Duty 1990-1999 334-2005 334-2239. I chose this alternator because it had a 95 amp rating, the correct form factor, and the correct belt drive pulley for my engine. Many of the 3G alternators come with a pulley for a serpentine belt, which would require swapping pullies. Not a big deal, but it saved me some work. The alternator I received did not require reclocking.
	PA Performance 1G to 3G conversion kit – This kit includes a new alternator wiring harness with the correct connectors. It also includes a dummy voltage regulator that replaces the original regulator. While not required since the 3G alternator has an integral regulator, it makes rewiring easier and permits retaining the alternator warning light without any additional wiring. I chose to use the dummy regulator to make my life a little bit easier. Many people choose to not use one.
	PA Performance premium power wire – This is the wire that connects the alternator to the battery. The original wire needs to be replaced with a larger gauge because the original cannot handle the increase in current from the new alternator. It also includes a 200 amp fuse and holder.

Wiring Modifications and Installation

After disconnecting the negative battery cable, I removed the old alternator and regulator. Then I installed the dummy regulator in place of the original and reconnected the original regulator wiring harness.

I preinstalled the conversion harness and new battery cable on the alternator before installing everything in the car. I decided to add some connectors to the conversion wiring harness. Since I was using the stator connector to power my electric choke, I needed to splice in a connector to the new stator wire to connect to my electric choke. I also added weatherproof connectors for the ground and ignition wires to make the install and maintenance easier.

On the wiring harness in the car, I added connectors to the existing ground and ignition wires from the old alternator. Then I taped off the old battery and stator wires as they are no longer needed. It is important to not connect the old alternator battery wire as it cannot handle the increased current from the new alternator.

Once all the wiring modifications had been completed, I installed the new alternator. It bolted right up in place of the old alternator with no issues. I was even able to reuse the old fan belt. Next, I connected the ignition, ground and electric choke wires to the conversion harness on the alternator. Finally, I connected the new power cable to the starter solenoid and reconnected the negative battery cable. No fires or sparks so I proceeded with testing the converted alternator.

I started the car and measured the voltage at the battery. It measured a solid 14.,5 volts at idle. The alternator was charging, so I marked this conversion as a success. I may go back and attempt to route the wires better, but for now I can move on to the next project.