1) The engine is not going to turn over - the starter motor won't run

Or

2) The engine turns over and often will not fire and run.

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This article will address the initial cause. If you engine turns over and can not fire see my other article.

Begin by checking the battery voltage. Most Jeeps have a voltage meter about the dash. If the voltage is low - below 10 volts, check the following:

1. Fist check to see if there is a reason for your battery being discharged. Were the lights left on? Doors left open or another power draining accessory left on? In that case, switch off the drain and employ jumper cables to start out using a charged battery from the different vehicle.
2. If there's been no excess power drain, look at the condition with the battery cables. Eliminate the cables from your battery posts and clean the contacts. Also check the connection from the ground cable towards the vehicle body.
3. If the battery cables are neat and making good contact as well as the voltage is still low, verify how the alternator is working correctly.

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4. If the battery continues to don't start your Jeep, replace it.

When the battery voltage is common nevertheless the engine still will not start, the most frequent cause is one of the safety interlocks. By using an automatic transmission there's a Neutral Safety Switch (NSS) that only allows the engine to start out in neutral or park. The contacts in the NSS can corrode and result in the switch the signal from malfunction. Move the shifter forward and backward while turning the key to start out. Often the motion will cross a place on the switch that still works. The NSS can be disassembled and cleaned or just substituted with a new unit.

If the NSS is working properly however the starter still is not going to turn, you could have a defective starter or starter solenoid. The starter and solenoid are replaced as a unit around the XJ Cherokees. However before selecting as replacement starter, check the wiring connection around the starter and also the trigger wire towards the solenoid. Often these connections can become loose or dirty as a result of rigors of dirt driving. Some individuals have reported that starters can be disassembled and cleaned to improve problems however have not tried this procedure.