HELLO 2 DAYS AGO WENT OUT to start 2000 MB Ml320 and zero at switch,a battery although battery is OK.Turned key to on and bridged the connectors at the Solonoid and car turned over easily .Removed starter and replaced solonoid.tried to start it again and just heard 1 click of starter and then nothing.Does not sound like it is engaging flywheel but not sure.jumped connectors again and turned over but would not start. Could it be bound up or defective? Thanks answers

If your grounds are good and clean, I would test the switch itself.

I would replace the starter and /or battery. Both can be checked at a parts store. Sounds like you may have a short in the starter, draining the battery.

You have a faulty ignition switch relay. It's responsible for using a low voltage signal (key in start position) to send full battery power to your starting circuit.

Check the make sure the battery connectors are connected. Sometimes the cable comes loose from the battery. Check your battery see if a jump will start it. If it does it could be your battery.

Ok...I can't really tell you exactly what's wrong because electrical problems require actual testing to diagnose. But, I'll tell you what I'd look at. First, check the connections on the harness that comes from the neutral safety switch. (yours should be located on the passenger side of the trans with the connector being up near the trans dipstick tube). In either park or neutral the switch terminals marked B&C should have continuity using an ohmmeter between the switch side of the connector. The switch should complete the ground that goes to the rear connector on the starter relay.(inside the power distribution center.) If you take the actual center apart,(only done with battery disconnected) you will find that connector has two small black wires that should be grounded in either park or neutral.
You can test the relay by swapping it with another of the same number (most in jeeps are the same except the one for A/C and ABS). Before getting into tearing anything apart, make sure the starter has a good connection from the battery (volts at the large starter terminal should be the same as battery voltage. Also make sure the small starter terminal has 12v when key is turned to the start position (careful doing that as if it starts your hands etc need to be clear of any moving parts). If not, then make sure the ground cable is clean and secure. If then you find nothing proceed with other tests I outlined. If this seems too complex or if you don't understand any of it, best is to either ask me and I'll attempt to clarify it or have a good shop go over it for you. Please DO NOT rate my answer if you don't understand it and haven't asked any further questions!!!

Sounds like alternator belt burned and broke.

Well, if you jumped the battery and it started, maybe you need a new battery. Get that checked out first. Also, when was the air filter replaced? I would probably take to an indy shop if it wasn't the battery or air filter because it could be a bunch of things: starter, fuel pump, fuel filter or fuel injectors.

I ran into the problem and it was corrosion on the battery terminals. on the inside against the battery. also check the the terminals for good connection.
Stay warm

Hello my MB ML320 wont start, only start if I jump it,i change battery but I have same problem it start if I drive for long time but if is park for more than 5 hours it wont start.

ignition switch,,or,,battery dead,,or ,,broken wire at starter