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Don’t Beat Yourself Up

Mercedes-Benz Windshield Wiper Fault

I try to remember to always slow down and look at a situation thoroughly. Often I am guilty of going too fast myself, but this story comes from a friend of mine, a tech, who had repaired a Mercedes Benz but was over-stressed by phone calls, clients in the waiting room, and helping his technicians.

He called me up and sounded very distraught and out of ideas. The wipers on the vehicle were not working. Having seen this before, he opened the hood, accessed the wiper motor and tightened up the loose pivot nut. The wipers still did not operate.

He started to tell me all the things he had replaced. First there was the wiper motor and transmission. He figured that there was a good chance that the motor just had an internal failure and the wiper transmission felt on the stiff side. But still no wiper operation.

Then he tested for a signal to the motor from the front SAM; since there was no signal, the front SAM was replaced. Still no wipers.

Thirdly he saw that the steering column module (SCM) was switching in an Actual Values page but the signal was not getting to the front SAM, so the SCM was changed. Again, no wipers.

You could feel a disturbance in the Force. This was a smart guy, and could back up the talk with spinning a wrench; he was not just a test-taker and parts-changer. We in the business do this not because we have a theory and wish to pontificate on it all day, but we want to test it and actually repair the car. I also feel that we are at times guilty of being so far into the trees that we cannot see the forest. My friend put himself deep in the brush here. Now, after a ton of time and money spent, there was still no wiper fix in sight. The client had been in the waiting room all day and was angry.

I asked my friend if the hood was open. He replied “Yeah the hood is open.” I had a bad feeling about this as soon as he had started his story. I told him to close the hood. There was a pause and then a loud noise; and then the sound of the hood closing.

I’m just writing this to remind us all to slow down once in a while. The fix may be right in front of your eyes.

It was a 2005 C230. It is true of all Mercedes Benz cars: the wipers will not run with the hood open