Great diagnostic work Dwight Giles Jr. Wickford RI
On Tue, Sep 29, 2020, 4:45 PM Floyd Thursby via Mercedes < mercedes@okiebenz.com> wrote: > So if you recall I bought this 05 ML500 in kind of a shady deal, $400 > for the vehicle, $275 to spring it from jail where it had been towed. > It had a "Start Error" which would not allow it to start. I spent a lot > of time digging into it with the majick computer, and managed to clear > the Start Error message on the dash. Was not apparently the keys and > code chips as those all checked out OK, the DAS (Drive Authorization > System, a little loop antenna around the key switch that reads the chip > in the keys) appeared to be happy. I had pulled a DAS loop and module > from a junker for cheap, they are like $175 new, did not need to use it. > > Still would not start, after doing some research it was suggested that > the starter power K11 relay in the fuse box under the hood was either > bad or it was not getting power to make it work. Swapped out relays > (there are a bunch that are the same), still no workies. Turns out > after doing some electrical diagnosis I discovered I could jumper the > relay contacts to get the engine to turn over and start with the key in > Run position 2 (all dash lights come on. (YAY!!!!). I put a momentary > contact switch on the jumper wires so I could lift the hood and turn > over the engine to start. (I tried to run it into the cabin but > couldn't find a convenient hole). > > So that suggested that an electrical switch behind the key lock switch, > that the key lock actually actuates to start the car, was bad in the > start position 3 -- positions 1 and 2 worked and I could start and drive > the vehicle in position 2. There is a way to test the switch and > wires right there at the switch (pink wire I think, marked #15?) but it > is tight in there so I didn't bother with that aspect, in any case that > wire is what goes to the relay activator contacts (these are the > contacts in back of the relay slot that are along the axis of the car, > the actual starter actuator contacts are the front ones that are > transverse) and I was getting no power to activate the relay. > > Common issue on these vehicles apparently, can make you crazy, a new > part is like $25 so I ordered one the other day. > > There are 3 covers to take off around the back of the steering wheel and > the various arms behind it. There are 3 Torx T25 screws on the bottom > one, some plastic tabs on the top one, and some tabs and metal snap > connectors on the right panel. They mostly pop out with release of the > tabs and a bit of gyration and having the wheel tilt up or down. > > The electrical switch is at 90deg to the key switch in a round housing. > They are (fairly) easy to pull once you get the covers off. Small hands > would help but I managed to get the connector off (there are locking > tabs with little arms you can squeeze with your fingers, although I used > a screwdriver to push the front lock tab you can see and managed to > squeeze the back one and the connector popped right off. Note that > there are some tabs on the top of the copnnector that slide into the > back of the lock and in the housing so it will only orient one way, > pretty much with the tabs on the top at 12 oclock if you could look from > the back. > > The actual switch is further inside the round housing, and there are > also 2 locking tabs that hold it in. You can feel inside the round > housing and get the tabs released, although again you can use a > screwdriver on the one if front. I could not get a good grip on it to > pull it out so got a small pair of pliers to grab a contact tab and pull > it right out. > > There is a small tab on the back of the key switch that turns the > ignition switch, it is like 1/4" wide it looks like, you can see on the > new one how it will fit over the key switch tab. The old one was > clearly chewed up a bit and it was hard to turn with a screwdriver even > if the slot was OK (which it wasn't) so that was the problem, the switch > wore out or bound up and would not turn to position 3 to start the engine. > > The new one slid in OK once I got the tabs oriented to the slot in the > housing, as with the connector, although I did have to put the key in a > move it a bit before the new switch would slide over it but that was > easy enough. > > Buttoned everything back up, took out my jumper switch, popped the relay > back in, and JOY!!!! Engine started right up. YAY ME!!!! I did notice > too that the key turned more easily so the switch was definitely > buggered from that indication as well. > > This time it took like an hour, next time would be like 20min. > > I"m going to put this in Benzworld with pics of all the bits involved. > > > https://www.benzworld.org/threads/w163-ml500-ignition-switch-no-start-fixed.3060413/ > > -- > --FT > > > _______________________________________ > http://www.okiebenz.com > > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > > _______________________________________ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
