HELP: Electrical problem with E300DT - PeachParts Mercedes-Benz Forum

EdzBenz · #1 01-14-2012, 09:16 PM

Fellas,
I have a problem on my hands that is is leaving me scratching my head. I was hoping someone could read my description below and help me identify what the problem could be.
Description of problem
I have a major problem while attempting to start my vehicle. Everything is normal when I insert the smart key into the ignition. The vehicle recognizes the key and locks it in place. Upon turning the key to the first and then second positions for starting is where I run into a problem. After turning the key to the second position, the speedo display goes blank. This means the mileage, temp, etc all goes blank. Then the car starts to make a series of loud clicking sounds which sounds like solenoids clicking on and off. This noise comes from multiple locations both inside the car, and in the engine bay. My cabin HVAC fan turns on blows air. This is really strange to me especially since the fan controls are completely off. My windows will not roll down. Trying to fire the engine up only produces a loud click too, and the starter does not engage. I hooked up my car to my Snap-On scanner tool and the scanner does not recognize that it is hooked up to my car like it normally does.

What was I doing to the car right before this problem occurred?
I was preparing for a 350 mile trip back home. I did my usual inspection of tire pressure, checking the engine bay for any leaks, etc. Everything looked great. I got in the car and it started up without any problems. Upon startup, I received a message on my dash indicating "low coolant". I shut the engine off and popped the hood. I looked in the expansion tank and the coolant level was exactly where it should be so I was a little confused as to why I was getting an error message. I pulled out my Snap-On scanner and hooked it up to the car to read codes. There were no new codes in the system after checking. There was one stored code which was a "drive authorization" code. i cleared this code and removed the scanner. I got back in the car and while attempting to turn the ignition over, I got the symptoms that I've stated above.

Any help? Or links to similar problems and DIY? I'm stuck and I need to get back on the road. Thank you,

bustedbenz · #2 01-14-2012, 09:55 PM

Get someone to hook up to you with jumper cables and try again. Clicking solenoids and weird electrical behavior are often, often, often the symptom of a low or dying battery. Cold weather brings out weaknesses in batteries that would have been fine in the summertime.

Even if this doesn't help it's a cheap possible fix. Unless of course your alternator has died.

EdzBenz · #3 01-14-2012, 10:01 PM

I appreciate your response and thank you. I forgot to mention that I did attempt to jump my E300 off the S500's battery after receiving these symptoms. During the jump, I still experienced the same problems from my original post with the clicking, no turnover, etc.
Two items to note as follow up:
-My battery is less than one year old
-My alternator is less than one year old
-My car is currently in a heated garage

bustedbenz · #4 01-14-2012, 10:08 PM

Quote:

Originally Posted by EdzBenz

I appreciate your response and thank you. I forgot to mention that I did attempt to jump my E300 off the S500's battery after receiving these symptoms. During the jump, I still experienced the same problems from my original post with the clicking, no turnover, etc.
Two items to note as follow up:
-My battery is less than one year old
-My alternator is less than one year old
-My car is currently in a heated garage

Well there goes that theory

I'm not familiar with M-Bs that new, but if I were stuck somewhere and had to get home, one thing I might try to do in your situation is turn the ign on and then use a screwdriver or jumper wire to manually put battery (+) voltage on the starter solenoid contact and see if I could force the starter to operate and the engine to start, bypassing all possible relays and circuits and so forth.

You sound like you know what you're doing, but it'd be careless of me *not* to mention at this point that doing this at night without good light is a good way to a) get yourself wrapped into your own fan or moving pulleys, or b) hit the starter + lug instead of the solenoid + lug and end up holding a very hot piece of jumper wire that suddenly got several hundred amps drawn across it, or c) accidentally short out the battery + wires to some metal part of the engine and end up with a literal arc welder in your hand. That being said --- with a really good light and with some careful studying, I might be tempted to do that to at least get the thing home where I could diagnose further.

bustedbenz · #5 01-14-2012, 10:10 PM

Some cars have jumper blocks on the fenders that make it really easy to do this without having to mess with the large wires on the starter itself. However, usually this is only on the older ones... my 1986 doesn't seem to have them anywhere. I started it that way for a few months when my neutral safety lockout failed, and had to work with the wires on the starter because I couldn't find any junction block that did me any good. My 82's, however, both have the screw terminals where you can get at them. I have no idea what a 99 looks like but I'd wager they've made it more difficult.

pimpernell · #6 01-15-2012, 07:40 AM

If I were you, I would try disconnecting the battery for a minute or two, and then reconnect it. You may have to recalibrate the seats and windows, and your owners manual should tell you how to do that. From your description of events, I would say that your problem is more than just the starter not engaging. If you have a spare key on hand, you might want to try that. Best of luck

TMAllison · #7 01-15-2012, 12:44 PM

I'm thinking K40/voltage or a DAS issue.

If you are convinced its not the K40 or voltage you might try re-syncing the key.

Does the steering wheel lock retract as the key is inserted? Thats the start of the security sequence.

EdzBenz · #8 01-15-2012, 01:29 PM

I appreciate all of the responses fellas. Last night I decided to put the battery on a trickle charge just to try and cancel it out as the problem. I figured since it was so new that this wasn't it, but thought it was good to be sure to cancel it out.
BustedBenz was right. It turns out that the battery was bad. Went to AutoZone today, got it replaced under warranty. Hooked up the battery and the car started right up. The weird stuff going on with the electronics and display, coupled with my battery being brand new made me think my initial problem was much more severe than this. Thank god I'm not replacing anything else now.
Thanks for the responses and help.