How to Replace the Alternator in a Jeep Grand Cherokee

by eHow Cars Editor

The Jeep Grand Cherokee has an alternator that sends electrical current to various devices in the vehicle while the engine is running. Most alternators made today include a voltage regulator that ensures the voltage level remains constant. You may need to replace the alternator if your battery keeps running down or your headlights become dimmer while driving.

Determine which alternator your Jeep Grand Cherokee will need. You'll want to be sure the new alternator is compatible with your Grand Cherokee's engine. Models made from 1999 to 2004 may be equipped with a 2.7 L OM647, 3.1 L 531, 4.0 L PowerTech, or 4.7 L PowerTech engine. Models built after this date can have a 3.0 L OM642, 3.7 L PowerTech, 4.7 L PowerTech, 5.7 L Hemi or 6.1 L Hemi.

Disconnect both battery cables with a socket wrench. Take the accessory drive belt off the pulley and remove the electrical harnesses from the alternator. Take the mounting bolts off of the alternator with a socket wrench and remove the alternator assembly.

Install the new alternator assembly and tighten the mounting bolts to the proper tension with a torque wrench. Torque the mounting bolts for the 2.5 L and 4.0 L engines to 41 foot pounds. For the 3.7 L engine, the horizontal bolts should be torqued to 42 foot pounds and the vertical bolt should be torqued to 29 foot pounds.

Torque the short horizontal bolt for the 4.7 L engine to 55 foot pounds and the other two bolts to 41 foot pounds. The bolts on the 5.7 L engine should be torqued to 30 foot pounds.

Connect the electrical harness to the alternator. Install the alternator belt and adjust it to the proper tension. Connect the negative battery cable with a socket wrench.

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