Hello all, 2005 Roadster, 33.5k on the clock, recently went for a ride only to be stranded 20 miles from home with the no crank, no start problem. Lots of details to report, and I am not sure what is relevant so I'll include all the details that come to mind.
Have had the car in the family for about 4 years, my Dad purchased it as a fun car / parade car to enjoy around my hometown in upstate NY and for short trips. It hibernated every winter, all winter. Previous to that it was in Florida, and NC (off lease in FL, auctioned and sold to 2nd owner in NC). I inherited the car, and shortly after, a string of issues cropped up. First, low battery (which was replaced in Fall 2017, but the car was jumped before the battery was replaced). Next, the roof quit working and was not completely latched. The rear bow wouldn't click all the way down and the trunk interlock was preventing it from opening. Solved that with some forum searching! (Thank you all!) I found one of the hydraulic roof lift cylinders leaking (no big deal, I shipped them to Klaus @ Top Hydraulics to have the 2 main lift cylinders rebuilt). Around the same time, I began having intermittent stalling issues, usually at red lights, but sometimes at low speed in the neighborhood. I've avoided any long trips because I did not have confidence that I'd make it home trouble free.
In the last few months, the intermittent no start condition became more frequent. I had read a great deal about the need for a GOOD battery, and it seemed like putting the battery on a charger for 30 min every now and then always overcame the no-start issues. I figured I would have to replace the one year old NAPA Legend battery, or possibly use a battery tender to keep the battery topped up as I do not drive it frequently. Thinking there may be a small vampire drain on the battery drawing it down enough that I would have these no-crank, no-start situations. One time, I assumed I had drained the battery down when washing the car, I left the car in the on position to raise the wing / wash under it. Blower motor was running for probably 15 minutes. Then no crank, no start, and wing part way up, would not retract. Did I get something too wet? Hooked up the charger again and left it on for a while, back to normal.
Fast forward to this past weekend. After a Saturday of yard work, I decided I'd earned some relaxation, and the fall weather was perfect for a top-down drive. Well, no crank, no start again. Hooked up the charger and let it build for 30 min. Tried it again and it was ready to roll. About 20 miles from home, rolling to a stop light, applied the brakes and the dash lit up like crazy. Brake wear indicator, Brake, BAS / ESP and ABS lights all on. The shift indicator (it's an automatic) went to a black rectangle, and the speedometer dropped to 0. At the stop light, it was apparently in limp mode, pulling away was obviously not in first gear. I made the choice to pull into an Advance Auto Parts store, to shut it off and restart, hoping the problem would reset. Oy, bad choice. I should have limped the rest of the way home. Pulled into the parking lot, put it in park, then realized I should back it into a parking space. No go, stuck in park, like the gearshift/brake interlock was blocking it. So, I shut her off. No crank, no start. I had Advance employee test the battery as long as I was there and stuck. Tested good, plenty of juice and CCA. Started reading through this forum on my phone, as my wife sat patiently in the car. I'm sure she was thrilled! I noticed many threads discussing bad solder joints on the RCM, so I pulled mine and looked with naked eye / no magnification in the now-fading daylight. Erroneously thinking it was good (see pics), I put it back in and began focusing on the brake lamp switch. (Noticed that there was no brake lights).
Roughly an hour later, I was about to give up and call AAA for a tow, to give my ever-patient wife a break, hoping I could convince them that we needed a flatbed. We walked to a nearby drugstore to use the facilities and gather some snacks, anticipating a really long wait for AAA. Leaving the store for the walk back to the car, I suggested - "How about we just start the car and drive it home?" Well, golly, it fired right up, but was stuck in park, I messed with the brake lamp switch a little bit, working the plunger back and forth and reinstalling it, and the shift indicator went from a black rectangle to "P". BINGO - put it in drive and headed for home. All indications were that everything was behaving normally, no lights except TPMS, I do not know if I had brake lights or not, as I drove carefully on the way, to avoid using the brakes as much as possible until we got into town and it was inevitable. When I hit the brakes, all the lights on the dash previously mentioned came back on, and the speedo dropped to zero again. Drove it the remainder of the way home and put it in the driveway. Turned it off, tried it again, no crank, no start. Ok, enough for one day!
Sunday, I pulled the RCM to take a closer look - hmm, yes, halos around all of the connections. I am not the BEST at soldering, but figured I didn't have a lot to lose, and would like to be able to put the car back in the garage. Using the soldering gun I heated the pins and reflowed the solder, adding in some rosin-core stuff. (See second pic). Looks better, but not great. Did I overheat it? Reinstalled it, no crank, no start. messed with the brake lamp indicator, no difference. Hooked up the charger again, and let it sit for 30 min or so. Fired right up. But the dash lights are still lit. Maybe I do need a brake lamp switch? Guessing here, but I assumed that my RCM repair was good enough, since it did start after charging. ???
Purchased a Mercedes oem brake lamp switch today, installed it this evening. No crank, no start. Put the battery charger on it for a while. No difference. Same lights are still lit (brake wear, BRAKE, ABS, BAS ESP) Frustrating. Hey, I should dig up my code reader. P0600 - no comms. Well, that's not very helpful.
Back to the forums tonight. I think it's possible that the RCM is worse than I thought, maybe with a traction control relay that is out of whack, and maybe my 'repair' attempt wasn't great.
What's next for me?? DJ, (tighed1) ?? OneHundred80, ala_xfire, Pizzaguy - looking for some words of encouragement, or maybe some soldering critique. :-)
Thanks in advance!
DadsXF
RCM - enlarged, before attempted resolder.
RCM after attempt.
Driving, speedo @ 0, shift indicator - black rectangle