Starting Problem W140 Diesel 300sd

[mbdiesel]

Well I am back to work on my 1993 300SD. It starts immediately with
remote jumper hook up. That is how I have been starting it. It starts occasionaly with the key. All grounds have been checked and are clean. What I am about to do is change out the auto transmission lockout switch located on the transmission. Also I have been studying the Alldata schemetics and was wondering if failure is due to alarm system somewhere , a relay or something is preventing current flow to starter solenoid, or some other relay. Checked all the relays in trunk of car and they appear ok. Next I will be going under the dash to see what relays are lurking there. I had this car for a while and love driving it. I have replaced the engine wire harness as the original was biodegradable. This has no effect on the starting problem which existed before and after replacing the engine harness. If anyone has
any ideas would like to hear them. Merry Xmas

Currently own 1987 300SDL - fantastic car - most reliable and mpg 25-31.
1986 300SDL W126
1993 300SD W140
1992 Toyota Camry

Previous owned 1984 300sd
1983 300sd
1970 240d 4speed manual -cannot break this engine - 60HP