Mercedes: 99 E300 Turbo Diesel - Starter wont turn over Engine, starter solenoid, dead silence

Question
This is the 2nd time this has happened to us. 1st time was on vacation in Florida last September...around noon we went into a store for about 15 minutes and when we came back out the car wouldn't start. We happened to be at a SAM's Club and their "technician" came out and said it was a battery issue so we ended up buying a new battery.  The car still wouldn't start.  We called for a cab and went back to the hotel.  Later that night around 9 we went back to the car and it started right up...drove straight to the hotel (about a 15 to 20 minute drive), tured the car off and tried to start it again and nothing...wouldn't start.  When we got ready to leave the next morning we drove straight home to Atlanta and never shut the car off for fear of not being able to get it started again.  My husband replaced the starter and it's been running fine since then. Yesterday we had to park it in the driveway for about 7 hours and when we went to pull the car into the garage the same thing happened again. The car won't start.  Even this morning the car won't start. Could this be a battery issue? Any help would be greatly appreciated!!!

Answer
Mary,
To be correct, are you saying that the starter refuses to rotate the crank? Is there a clicking noise from the starter without rotation. Is there dead silence when you turn the key to the start position.
OR, is the crank rotating and a no start condition.
I suspect that you have a bad ground in the starting circuit. I would check the starter solenoid.
Corrosion on all grounds can affect the ability to get enough amperage to the starter. Diesels, because of their higher compression require considerable torque to rotate the crank during start-up.
Make sure that the terminals on the battery are very clean, Make sure that the ground wired to the block is very clean. Make sure that the starter solenoid terminals are clean and tight.

Many time after a terminal get hot, there is too much resistance to the current to allow the energy needed to turn the starter.

Good Luck, let me know what you discover.
Rob