Ignition on and nothing happens, checked battery and is charged checked all fuses and breakers and all are ok, got underneath car and shorted across the starter solenoid end the engine would turn over but not fire , what should i check next?

Hello. Your Mercedes E320 has an electrical 'short' somewhere. Check your cigarette lighter and other 'power point' accessories. That 'short' is not bad enough to 'trip' a circuit breaker or fuse but it will 'drain/discharge the battery in time. Good luck and keep me informed; if you want to.

Could be a bad battery. Should get it tested to see if it holds a good charge.

You have a short somewhere and you need to trace the wiring. For your diagnosis, use "circuit breaker" fuse which will auto-trip/reset if there is a short or high amp draw. I even replaced some of my fuse with circuit breaker.
http://www.autozone.com/electrical-and-lighting/circuit-breaker?filterByKeyWord=breaker&fromString=search&newYmme=true

check connection and wires at battery for damage or corrosion if good check for power to ignition switch if no power check for damaged or shorted wiring if good turn key and check if power going to relays or accessory's at fuse panel if no power switch may be bad

may be you should make a diagnostic and you can do it in a garage or you can do it by yourself if you want to do it by yourself you need some tools and you can find some good ones here: chinasinoy.com

Sounds like the ignition switch, but it could be any of your other guesses too. When you turn the ignition switch do the accessory lights come on? If not, definitely the switch. Do you hear a faint clicking noise (the spark plugs igniting)? If so, it could be starter or the solenoid. It oculd also be the switch that allows the engine to start because the clutch is depressed (or the car is in park). if that switch is bad the car won't start because it thinks its in gear. Also be sure your battery is in good shape. It could be that after a short trip the battery isn't charging enough to start the car. You can test this easily next time it happens by checking voltage across the battery. It needs to be at least 12 volts. Anything less and the car probably won't start.

have battery and charging system checked. you may have a bad starter.hope this helps.

I would check with vom voltage at battery terminals and at starter to ground. Is possible could be a fuse or fusable link but I think the positive goes straight to starter and power distribution fuse or fusable link

check you fuses and clean your battery terminals, you might have a relay that controls you ignition. or could be your coil pack.

Hello,

I had the same problem with mine. Disconnect the power seat moduale underneath the seats. Recharge the battery and shouldn't happen again. Providing the battery hasn't worn down past the charging point. Worst case you will have to get a new battery. If you google C320 battery drains you will see hundreds of other peoples posts.

Good Luck