Hi - I have a 1995 E320 wagon that began giving me crank, no-start problems yesterday. Would not start after work last night, cranking but giving me a bouncing tach needle. I got it to start after turning the ignition to on for 90 seconds, turning it off, and then it started. ASR light was on but surprisingly no driveability problems for the 15 mile ride home.

Would not start again this morning, battery fully charged, cranks but no start, and now the tach does not move. Tried to pull the codes with a code reader that I have used successfully before. Ignition to on, plug in reader, and the LED comes on dimly before pressing the button. Press the button and it comes on full brightness; release and LED goes back to dim with no blinks.

Disconnected and reconnected battery, still the same.

Have searched a number of sites and have come up empty. What would cause the diagnostic system to act this way? Bad OVP relay?

Note: I have had previous intermittent ASR lights with the reduced power symptoms, but I have always been able to pull the codes. I have a replacement ETA to install but have been waiting for warmer weather (winter is still here in Mass.)

Thanks in advance for any advice on this.

95 is still in the era of biodegradable wiring insulation, searching this site will net lots of information. Disconnect the battery immediately and don't hook it back up until you inspect the engine wiring. When insulation falls off, all sorts of damage / bad things can occur.

I should have mentioned both the main harness and lower harness have been replaced.

Replaced with non bio insulation or replaced with another harness that is still bio?

You got me paranoid enough to go check - FD date on the Delphi label of the main harness (done by the previous owner) shows 2005. The lower harness was done by my mechanic in 2015.

I'm hoping the replacement main harness is not going south after 11+ years.

The delphi harness is supposed to be the good one. I'd take apart ground points and clean them, MB tends to pile a bunch of grounds in a single bolt, this can lead to odd behavior.

Past that I don't have enough time working on the older system so others will need to pick things up from here.

If you spin the engine to start and you see no movement on the rev counter is a sure sign of crank position sensor fail . Or even EZL if your car has one fitted.

Follow-Up: I replaced the OVP relay and Fuel Pump relay and the wagon started right up! And the diagnostic system is now working again allowing me to recall the blink codes. Gave it a good run on the local roads and the interstate with no issues or warning lights.


Both relays were dated 1994 and both fuses were intact. I did also clean the 5 grounding points and ground wire ring terminals in the engine bay with emery paper and Deoxit; some mild oxidation but nothing severe.


Running voltage at the battery is showing 14.48v no load and 14.32v with headlights on and HVAC fan at medium. This seems a little high and perhaps the next step is to replace the voltage regulator. Not sure if this caused the OVP relay to reach its end of life.


Thank you for the above suggestions.