OK, I don’t know how to do this other than to write a book about it, but I must provide a little history on the problem. This is a ’95 E420 M119 Benz. When I acquired the car, it had an aftermarket security alarm installed. The previous owner said not to use it because the dealer informed him of electrical conflict issues with the factory system that were causing problems. No problem. Months go by and all is cool. Then one day while driving, it just shuts down, and I mean dead…no power to anything but the headlights. After an hour or so, it just starts right up and goes a few days and does it again. Finally the frequency and shutdown intervals got to the point of absurdity!
I decide that it is the aftermarket security box, so I pull it into my shop (after it decides to start) and start tracing the roots of the problem. I finally find the box and found that the MORON that installed the aftermarket system actually removed the Benz module and cut over a dozen harness wires to tap this new box in just so they could have a button on their key chain! It was a real hack job deluxe!! After several hours, I had the factory harness restored back to its original state, (no, there are no crimp connectors anywhere!). I re-connect the batt. and everything powers up just fine, it just won’t crank because the starter lockout is part of the module function. So I ordered the correct security module as per VIN. When the mod. Arrives, I plugged it in and it started right up!! TO COOL!! Problem solved…or so I thought! I drove it to get some gas and it died at the pumps. Waited several minutes and it started up again. I made it close enough to the shop to coast in when it died next. Only intermittently has power returned while troubleshooting.
I logged on to the site and got a lot of helpful pointers and followed through on all of them, but to no avail. I have cleaned the batt cables twice, pulled every fuse I could find and brushed the ends, re-installed and confirmed continuity. Pulled every relay under the hood and checked them and their fuses where app. I have re-checked the harness where it was repaired and re-traced all of the steps I have taken from the start, and still nothing. I have the service CDs and they have only been marginally helpful, lots of discrepancies in relay locations. There is power to the headlights and the main terminal junction behind the ECM box(battery in trunk). But there is NO power going into the cabin or through the fuse panel except when the headlights are on. I’m really at the end of my rope here! I know it has to something very basic I’m missing, but I can’t seem to find the forest for the trees! Is there anyone who can help me in the dilemma?
Thanks, Edwin

By the way…1995 E420 VIN: WDBEA34E4SC241781 Mfg. Date 3/95
Engine: M119.975

 

if no power going inside... can't it be from the ignition switch?

 

No, I haven't checked the ignition switch yet, but you can bet it will be checked 1st thing mon. morning! I was also wondering about the voltage overload relay. I've read numerous threads about those being weak and/or giving intermittent problems...but I can't seem to locate the one on my particular car. There are several discrepencies on the relay diagrams and this relay is one of them. Any more thought on the matter??
Thanks!!

 

ok your ata is not going to cause the car to die so forget about that. check your ignition switch. there is also a small wire coming off the positive battery post with a 10mm nut on it check it for tightness. remove your fron fuse box check for a 30 and a 15 circut there its all sound so ignition switch. another way to check your ignition switch is get the car running and jiggle the switch back and forth but not turning the car off. just enough to wiggle it(the key) id the car dies them relaced the electrical portion of the ignition switch there about 25 bucks

 

it's overload protection relay. mainly it only protects the electronic units such as engine control unit, abs, asr, etc. the interior is still suppose to have power.

kindly check the terminal block inside the cabin (X4 or X4/1) for any loose contact. clean and re-tight and see if the problem comes back.

[IMG]local://upfiles/1/C7D988015FCA43908A70CC4D7A41AF7D.jpg[/IMG]

 

WWOOOOOHOOOO!!! Found the problem!! Thanks Sleepwalker for the thumbnail of that junction block. I went there first thing getting to the shop and at first didn't see anything wrong. I started probing with my test light and the system came alive!! Apparently, when this car went down the assembly line, someone was napping and didn't notice that the eyelet on the main power wire to the ignition switch didn't go over the stud before putting on the next wire and screwing it down! It sat there barely under the top wire and finally melted away enough plastic in the bottom of the block to start losing power intermittently when it would heat up. I removed the nut, pulled the top wire off, put them on in their respective order, tightened them down and all is well with the world. I really put the electrical system through the paces numerous times today trying to make something, anything happen, but it is back to being rock solid!! At least until something else wormy shows up.
THANKS AGAIN SLEEPWALKER!!! I can start growing my hair back again!!

TxQuigly

 

am happy you got it sorted out.

you're welcome.