• Use this style adapter if vehicle is w/o alternator warning light or if vehicle has voltage gauge & no warning light.
    • Adapter for the Conversion of SI to CS Series Alternators.
    • Harness allows new style (CS Series) alternators to be used in older vehicle applications (SI Series).
    • A rear support bracket is recommended on the CS alternator conversion if a rear support bracket was on the SI unit being converted.
    • It is recommended that an SI to CS conversion having an warning light present use JT&T #2771F adapter (a voltage gauge package can be present, but must include a warning light). If no warning light is present, use JT&T #2770F adapter.
    • It is also recommended to use a warning light or wire resistor when installing ? failure to do so could damage the alternator.
    • Replaces GM #12102921, 88861073, 90196375.
    • Replaces AC/Delco #8078, PT2145, D-856A.

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? WARNING: Cancer and reproductive harm - www.p65warnings.ca.gov

About Alternator Conversion pigtails:

JT&T offers two different alternator conversion pigtails that allow you to easily switch between older SI series to newer CS series alternators. In addition to providing less amperage, the older SI alternators also required more RPM to charge properly. That means at idle or cruising speeds, you may not be properly charging your battery. That makes this upgrade very worthwhile.

The two conversions are part numbers 2770F and 2771F. Although they look very similar, they are in fact different. They both feature a two prong terminal on one end and a four prong on the other end. In addition to using different gauge wires, they connect the two on the one end to different prongs on the other end. All these accomplish is to adapt from one style plug to another, you may need to make other changes to your wiring to complete the conversion.

Cars with alternators warning lights have differently configured wiring than those without. It is important that you determine which you have before ordering a conversion pigtail. CS series alternators require a certain level of resistance to operate properly. Not enough resistance can cause early failure. In cars with a warning light, this light serves as the resistance. In cars without, you must add it either through a resistor or resistance wire. We recommend you properly investigate this before proceeding. Googling "SI to CS alternator upgrade" will yield some good information.

If the car originally had an externally regulated alternator, you will also have to address that.