Alternator Help & FAQ's

 High Output Installation Tutorial Videos

Directly from AutoTech Engineering


Installing Your First High Output Alternator
If you are Installing your first High Output Alternator or just need a refresher, this will cover all the information you need: 
English & Spanish:
2 Wire Harness Bypass
 Wire Harness Installation for Voltage Bypass Harness (2 wire harness) is NOT to be Connected to your Factory Harness   
English:       Spanish:
External Voltage Regulator
English:       Spanish:
GM - 3 Pin Plug Harness Instructions (Long Version Detailed Video)
PCM Frequency voltage controller installation
Purchase it here: GM Voltage control Unit (


Frequently Asked Questions



Serpentine or V Belt OEM Lookup
Looking for the proper belt size but don't know what your original belt size is? Use or OEM belt finder and our Belt Chart by sizes and contact any Auto Parts Store (we prefer Napa).  We suggest you order 2-3 different shorter belts to avoid multiple trips to the store and return the ones you end up NOT using.    
Use our Belt chart lookup to First find your Factory belt. Once you have found your belt number (ie: 5060468) you can now look up that part number and select the shorter belt sizes on our belt chart link 
5060460 6PK1170 46.06 46.72 .82 6 W ( 3/4 shorter)
5060463 6PK1175 46.25 46.91 .82 6 W (1/2 shorter)
5060465 6PK1180 46.50 47.16 .82 6 W (1/4 shorter)
5060468 6PK1185 46.75 47.41 .82 6 W (original belt)
Belt size and tension:
A smaller diameter pulley is normally supplied unless otherwise stated to ensure you receive the maximum idle output. DO NOT SWAP OUT ANY PARTS FROM OUR UNIT OR YOUR WARRANTY IS VOID!   A shorter belt is usually required, USUALLY AROUND HALF INCH SHORTER on average. We recommend you purchase 3 shorter belts to save yourself multiple store trips. Ensure you belt tension is tight as well. Slippage of a loose belt will cause alternator not to function properly and will cause Premature failure. 

Boosted Harness:

Need to charge higher than OEM voltage? Then pick our boosted Harness option.  By picking this option your harness will come already dioded for you.  You can pick from three options for charging voltage 15.3, 15.5 or 15.7. 

Big 4:
Alternator positive cable that runs to the positive terminal of the battery. Negative battery cable that runs from the battery to the vehicles chassis. Chassis grounding cable that runs to the engine block
We recommend adding a 4th ground cable which runs from the clean part of the alternators REAR casing (aluminum exposed) to vehicles chassis for increased voltage output. Ground Lugs have been strategically placed for your usage on our Powder Coated units.
Powder coated units:
Powder coat on alternators is a “ground killer”. Most assume the alternator is not working if above has not been completed properly. Proof of voltage and amperage output was sent to show that we shipped you a functioning alternator. If your unit is not charging or has LOW voltage, you need to verify that you did the above steps correctly. Most of the time, we find that a step was skipped such as the extra ground from ALTERNATOR TO CHASSIS, so we added a ground lug for an added ground option.
Charging low voltage, IDLE RPM low or NOT Charging once installed:
See “Big 4” and Belt size and tension topics above. Most issues are resolved with the first 2 steps.  If you replaced your belt, pull on your belt by hand.  If you can pull on belt and feel tension lifting up, then your belt is still loose. IDLE RPM must be at 650rpm minimum for achieve maximum performance. 
Testing your alternator to verify output:
If you do not have a Clamp meter for voltage or amperage testing, please purchase one. They are very inexpensive and safest way to test voltage and amperage of your alternator.
Please DO NOT disconnect your alternator from battery while car is running to test your alternator. This is the quickest way to do damage to your newly installed unit (and we can tell). Doing so voids your Warranty.
1 Wire alternators and/or Plug Harness (if supplied):
If you ordered your alternator as a self energize or 1 wire, please remember that you no longer need to use the cars harness that was once plugged into your old alternator. This harness can be “tucked” away. Only connect positive battery cable to positive post on alternator and you are ready to go. If you received a plug harness with a loose "blue/Sense" wire, this will get connected onto the Alternators positive post. Any voltage bypass harness are explained in the above videos.
Voltage bypass or PCM/ECU bypass:
Unless otherwise quoted or instructed, our units come supplied with the OEM Voltage output for PLUG and PLAY alternators. Voltage settings quoted are already built into the Voltage regulator inside the alternator. A reminder that PCM and ECU type vehicles means that your vehicles “brain/computer” controls the voltages. If you are looking to bypass your PCM or ECU control, those options are available, just contact us and we can customize a Voltage setting for your and your Batteries.  If you received a plug harness with 1 loose wire, connect this to the Alternator Positive Post.
Rear Foot Delete options:
Some of our High output alternators may arrive to you missing one of the Rear mounts of the alternator.  In order to build a “True” High Output alternator, we have to eliminate the rear alternator mount a times.  They alternators fit and most of the time you simply need a spacer a and lock nut to hold the alternator to the engine mount.  
Battery Reserve Recommendations:
Battery Reserve is critical for ensuring your High Output Alternator performs as expected. Simply getting a High Output Alternator and using a "Walmart" battery will not keep you from ongoing Voltage drop.
We recommend the following for proper reserve:
  • AGM Batteries: 50AH for Every 1k Watts
  • If you are running 5000 watts then you need 250AH of Battery Reserve
  • Lithium Batteries: 10AH for Every 1k Watts
  • If you are running 5000 watts then you need 45-50ah of Lithium Reserve.

Technical assistance:

If you need any technical assistance, please contact us or AutoTech first.

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