External 12 Volt Voltage Regulator

By | October 1, 2014

Recently I had the computer go bad on my 2000 Dodge Ram 1500. Not the whole computer, the truck ran fine, but the part that regulates the voltage output from the alternator. After looking online I found a kit that is sold on eBay that uses an external voltage regulator to bypass the computer and control the alternator output.
The engine light stays on but the voltage now is regulated by an external regulator. This is a great money saver if you have ever priced a new computer for a car or truck you would know.

Here is a video on How to make a External voltage regulator your self.

This circuit can also be used in other requirements, or anywhere 12 volts needs to be regulated from HVAC to a alternator.
Below is the information for this that came with the kit and how it is installed, which is quite easy.
external voltage regulator
The voltage regulator needs to be mounted on the fire wall or fender well. Grounding the regulator is important otherwise the voltage will fluctuate. Sanding the area where the regulator is mounted is often done to insure a good ground. The kit comes with a green wire to go from the voltage regulator to the alternator to be sure a good ground is in place.
The wiring harness comes with three wires. Two black wires and one red wire with a inline fuse.
The two black wires go to the alternator while the red wire goes to the battery through the fuse box.
Black wires
Two leads are located at the back of the alternator which go to the computer to regulate the voltage. These two leads need to be replaced with the two black wires in the kit.
Be sure to cut the connection of the two leads going back to the computer. No voltage or wiring goes back to the computer. Tape them if they are open connectors so they don’t short out and place them out of the way.
The two black wires connect to the alternator were two leads are located. These are the two leads that used to go to the computer to regulate the voltage
The two leads can be used interchangeably and do not matter which black wire they connect to. There is also a large existing alternator wire that goes to the battery this should be left alone only the two leads going to the computer need to be used.
If none of the connectors in the kit work with your alternator leads then the old connecting plug will need to be used. Cut the wires far enough away from the alternator to be able to reach them easily and connect them.
Red wire
The red wire on the kit harness with the fuse needs a connection to the battery. It cannot be connected straight to the battery otherwise the battery will drain when the vehicle is not running. Connecting the red wire correctly in the fuse box will break the circuit when the key is shut off. A 20 AMP fuse or bigger connection should be used.
Alternatively a switch can be used that runs to the battery separately and turned off when the vehicle is not running.
If the vehicle needs to be up and running quickly the fuse on the red wire can always be removed when the vehicle is off but this should only be temporary.
Green wire
The voltage regulator needs a good ground to the alternator or it will not work properly. To be sure the voltage regulator is grounded with the alternator the green wire in the kit should be placed between the voltage regulator and alternator. Be sure the connections are tight to insure a good ground.
After all the connections have been connected a digital multi meter should be used to verify the regulator is working. Using the meter to measure DC voltage, place the leads on the positive and negative battery terminals. With the vehicle running the voltage should be between 14 and 16 volts DC depending on the load.

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