Car won't start occasionally - 2003 Mercedes SLK 230

Hello all,

For the past couple of years, I’ve been having issues with the car not starting and was hoping to get some opinions on the possible cause. A new battery and starter were installed within the past year, which seemed to have fixed the problem for a little while, and it’s had every kind of tune up under the sun. However the day after the starter was installed, the car wouldn’t start the first couple of times I turned the keys. My extremely reliable and trustworthy mechanic looked over everything again and said he could find no issues whatsoever.

Since then, the car has failed to start every few weeks to months. Sometimes, it starts after a couple more tries and a short wait. Other times, a jump start gets it running. One time, i turned the keys, and the lights inside started flashing and a weird buzzing noise came from the stereo. The car wouldn’t jump start, but a couple hours later, it started up just fine without any help. I took it to my mechanic, who again coudn’t find anything wrong. I’ve taken it to multiple shops who have checked the car top to bottom, from the battery cable and terminals to the starter, and said the same thing. Today, the car wouldn’t start, but the lights came on and there was no clicking noise. I suspect that a jumpstart will work, but some of the mechanics have suggested that I have it towed as is to make it easier to diagnose the issue, but it’s an added cost that I don’t know I can manage. So I’m also wondering if I really do need to have it towed and and how I can find a mechanic who can actually find and fix the root of the issue. I’ve tried to call ndense the info as much as possible, so let me know if any further details would help.

Thanks in advance for your input!


The first thing to try is your other key . . . you do still have it, yes?

When it doesn’t start, immediately try the other key

If it then starts, I believe you have found the problem

If that doesn’t resolve anything, there’s a pretty good chance the ignition switch is faulty. The mechanical and electrical portion are one piece on this model, I believe

If somebody diagnoses the ignition switch as being the issue, that is NOT something an independent shop is normally able to do. They might be able to install it, but they won’t get the engine started. I won’t bore you with the reasons

You’ll also want to get the car looked at by a shop with very high quality, or even factory level, scan tools. There might be some helpful fault codes, which might speed up the diagnosis and repair. A lot of the aftermarket european software is near useless

But it might be something relatively simple

My son-in-law has a '94 Grand Prix, and when it wouldn’t start he had it towed and got it fixed. Pry open your wallet you cheapskate. ;-]