Try this if your Jeep Grand Cherokee won’t start:  By a guy who knows nothing about cars but has had lots of trouble with his Jeep.

1. If the accessories don’t work and the engine struggles to turn over, it’s probably your battery.  Try to jump it.  If that doesn’t work, or if it only keeps your car running for a few minutes, the battery could be bad as a result of a bad alternator.  The easiest way to check this is to buy a battery checker thingy for about $10.  This will tell you if your alternator is working and the charge on your battery.  Seriously it sounds like a hassle to go buy it but it’s worth it.

a. If you do manage to get your car started by jumping it, the alternator will charge your battery.  If you’re car dies shortly after all this, it could be that a fuse has blown in your power distribution center due to the overload from the alternator trying to charge your battery or something like that.  All I know is that it happened twice that after I killed my battery by leaving my lights on or something stupid like that, as I was driving around trying to charge it back up, my car died and no amount if jumping it would help.  The first time I paid to have a new alternator put in.  The second time a guy at the shop changed the fuse and sent me on my way.  I tipped him twenty bucks and cursed the first guy who probably charged me $200 for changing the fuse.

2. If the accessories work, try banging on the starter with the back of a screwdriver.  The starter is located about a third of the way back, under the passenger side, very close to the oil filter.  It’s above the exhaust pipe that travels back from the engine to the muffler.  Bang on it a few times and then try to start it.  Worked for me.

3. If the car starts but then dies shortly thereafter, it could be your anti-theft system.  This could especially be the problem if your battery has recently been disconnected as disconnecting the battery makes the car think its being stolen for some reason.  Use your key fob to arm the system then unarm it and try to start it.  You may need to wait about 15 minutes between tries to allow the system to reset.  You can also deactivate the alarm system by using the lift gate using the key and sometimes by turning the key left then right in the drivers door.  In some models of Jeep, unlocking the passenger side using the key will deactivate the alarm.

4. If banging on the starter doesn’t work, it could be your Neutral Safety Switch (NSS).  That’s the thing that won’t let you start your car unless it’s in Park or Neutral.  Try jiggling the gear shifter to make sure it’s in park.  Also, try starting it in Neutral.  An easy test to see if your NSS is working is to turn the key to the on position and then put the shifter in Reverse.  Your Reverse lights are also connected to the NSS so they should be on.  If they aren’t on, you know the problem.  If they are on, check the fuses.

5. The fuse associated with the NSS could be bad.  Check the to see if its blown. Also check the relays in the Electrical Distribution center are good.  I did this by trading out the one that operated the horn.  If the horn worked with the relay, the relay was good.  All my relays worked fine.  If you find a fuse or relay that’s blown, you’ve got an easy fix.  If not, well, I can’t help ya.

Hope this helps the guy who is frantically using his phone to search for answer on how to fix his Jeep Grand Cherokee that won’t start.