M-103: too many issues for the title... - Page 3 - PeachParts Mercedes-Benz Forum

400Eric · #31 01-05-2010, 10:11 PM

Were you breastfed as a baby Dave? I'm just wondering cause you're so smart!

I forgot to mention that I also made sure that there wasn't anything under the seats touching something or causing something to touch something that shouldn't have been being touched and maybe causing this problem. I then checked the meter again and the .70 drain was still there.

Unplugging the seats will be my next move. Any more ideas out there?
Regards, Eric

tinypanzer · #32 01-05-2010, 11:19 PM

Probably a good idea, and not all that difficult, at least on a 126.

On my 560SEL, I had problems with the seat tilt not working.

After much investigation, I found that a busted seat bottom spring had cut through 3 of the 5 wires in the harness going to that motor. The wires were touching each other, the seat frame, etc..... So, maybe check for something like that if you're under there.

Could it be that the relay itself is drawing this 7/10 of an amp? A relay does have a coil that draws current when active.......... Perhaps an internal short in the relay?

See if the relay is getting coil voltage when it isn't supposed to be also. Perhaps whatever controls that relay is sending it voltage when it shouldn't be. I don't know that a relay coil would pull .7 amps at 12v, but it doesn't sound too far off.

400Eric · #33 01-05-2010, 11:30 PM

Quote:

Originally Posted by tinypanzer

Could it be that the relay itself is drawing this 7/10 of an amp? A relay does have a coil that draws current when active.......... Perhaps an internal short in the relay?

That's what I was thinking originally but it's still pulling .70 amps even with that relay pulled out.
Regards, Eric

hispassion · #34 01-06-2010, 09:20 AM

GSXR's method IS the fastest way to solve a short circuit issue. If it's less than a 10 amp draw you can connect a DVOM between the positive cable and the positive terminal of the battery. With the meter connected, then begin pulling fuses (one at a time) to find the suspect circuit. Usually, it's something simple once you find the suspect circuit. One time on an american car, I found the seat bolted through a wire to the floorboard. Another time, I found a broken tail light bulb where the filaments had crossed. I'm not saying these are you issues, but only pointing out it's usually a simple fix, once you find the culprit.

Short of doing that (pun intended), you could try - as GSXR said - to remove the fuses one at a time while connecting the battery and watching for this loud spark you described. If the spark doesn't occur, you have found the suspect circuit.

Also, since it's a battery drain with the engine off, I would be only suspect of the circuits that operate without the key. i.e. the seat switch/motor/wires that operate with the door open, etc. Again, probably not the seat or switch, but I think you may be getting the idea...

Good luck!

cheeseraid · #35 01-06-2010, 12:30 PM

Your performance loss is either bad plugs, bad cap, bad wires, clogged injectors, bad ovp causing limp mode, or the most likely the eha is outta wack. If you got a dwell meter test the car at idle and 2500. Just plug the positive wire into the number 3 socket on the right fender wall next to the abs module. It should read somewhere between 45-55 at idle and 40-45 at 2500. My car with the 2.6 m103 likes 52-54 at idle and 42-45 at 2500. My car goes like a bad outta hell. My benz didn't want to start when it started to get cold and somehow the mixture adjustment got outta wack again. I check that mixture adjustment every six months. You electric draw problem I would pull the fuse for the seats and see if that stops it. I have seen quite a few of these cars draw electric from a bad seat motor. If that dosen't help pull all fuses except what you need to run the motor and work backwords putting a fuse in at a time and check current draw. The abs light could be a faulty speed sensor (there a magnet pickup in the front hubs). Just check that the sensor isn't gummed up. If not that then your abs module might be acting up. I don't remember how to test that thing. Anyways good luck.

400Eric · #36 01-06-2010, 11:12 PM

Thanks guys. Just about everything is resolved now except for the power drain which it seems is being caused by something in the power seat system. I've chronicled the cures to the other issues in posts subsequent to the earlier posts on this thread.

Didn't mess with this car today as I've got other fires to put out too. I've also got to get the 400E ready for track day!

Dave, where's that sense of humor that you got off of E-bay? I gave you a perfect opening line! A good response would have been: "No, but I was just last night!"
Regards, Eric

400Eric · #37 01-10-2010, 02:53 AM

Just gonna live without that fuse and relay for now. I just don't have the time to monkey with it. Too many other fish to fry. At least we narrowed it down, stopped the battery drain, and cured the other issues outright! (At least the ones on this thread anyway.)
Thanks again to all who helped!
Regards, Eric

400Eric · #38 03-14-2010, 03:37 AM

Thanks to this recent thread http://www.peachparts.com/shopforum/tech-help/272688-searching-voltage-drain-need-help-interpreting-results.html#post2425670 , I now have gotten to the bottom of this.

Back before I even started this thread, I had removed the back panel inside the trunk to gain access to the vacuum unit that locks/unlocks the trunk so I could find a leak I could hear but not see. I had been having trouble with the locking system because of that leak. It turned out the unit itself was bad so I left everything apart till I could get a replacement unit at the U-Pull-It. I did plug the air line so the rest of the system could work properly once again. Unbelievably, the pin that controls the trunk light lines up with one of the pins that holds the back panel in place. Panel pin missing = trunk light pin not being put into the "closed" position when the trunk is closed. I now have two business cards wedged into that area which has solved the problem! No more current draw! (Actually, it's .02 to .03 now and with the clock's fuse removed it goes down to .01).

I have already obtained another locking unit..... just have to install it now.

Why the relay for the power seats somehow seems to be involved is still a mystery. Plugging that relay back in now has no effect on amp draw readings.

The failure of the trunk locking unit led to the light staying on all the time which led to the dead battery which led to the jump starts which led to the OVP fuse getting blown which led to almost all of the other symptoms. So almost all of my troubles can be traced to that stupid trunk lock failure!

Closure!
Regards, Eric

gsxr · #39 03-15-2010, 11:27 AM

That is hilarious! But, I'm glad you finally pinned down the root cause... nice work, Eric!

400Eric · #40 03-16-2010, 01:27 AM

Quote:

Originally Posted by gsxr

I'm glad you finally pinned down the root cause...

Pun intended?

gsxr · #41 03-16-2010, 10:25 AM

Quote:

Originally Posted by 400Eric

Pun intended?

Ba-dum-BUM! *cymbal crash*

400Eric · #42 03-19-2010, 06:52 AM

Quote:

Originally Posted by tinypanzer

Also check to make sure the light in your glove box and trunk are shutting off.

I came back to this thread to look for a link and I saw this post again. It looks like Tinypanzer deserves kudos too because he pegged the trunk light as a potential source of the power draw. It just didn't seem right to not recognize his contribution to this effort even though it took another thread to get me to actually look in that direction. Kudos to the Tinypanzer man!
Regards, Eric