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rpmdiag
rpmdiag, Tech and Instructor
Category: Mercedes
Satisfied Customers: 7066
Experience:  Since 1975
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2012 R350 with 63,000 miles. takes 3-4 key turns to start in

Customer Question

2012 R350 with 63,000 miles. takes 3-4 key turns to start in cold weather (below 32 deg). No slow turn-over, just nothing - no sound, no solenoid clicking. Then on 4th or 5th key turn it starts right up !! Runs just fine then. Battery checked out ok, alternator checked out ok.
JA: Does the battery look like it's leaking? And does it have a strong smell -- like sulfur?
Customer: nope, looks fine with full charge present
JA: Are you fixing your R350 yourself? What have you tried so far?
Customer: just checked battery & alternator, nothing else. has been happening since we got cold snap here about 3 weeks ago & down to 17 deg here yesterday.. (we are in central Texas).
JA: Anything else you want the mechanic to know before I connect you?
Customer: that's it
Submitted: 1 month ago.
Category: Mercedes
Expert:  rpmdiag replied 1 month ago.

Hi, I'm Ron and I will be helping you today.
Stand by for a moment while I prepare your answer.

Expert:  rpmdiag replied 1 month ago.

High resistance in the cables or starter motor will cause this.

You may also want to check the resistance in the ignition switch as well.

Thanks, Ron

Customer: replied 1 month ago.
Sooo, how do I check the resistance in the ignition switch ? Only happens in COLD weather.
Expert:  rpmdiag replied 1 month ago.

That's when resistance is highest, when it's cold.

You need to use your ohm meter.

If you are satisfied with my answer, I would greatly appreciate a 5
star rating now and I will still assist you after you have rated me
too if another question pops up. I don’t get credit for helping you
until you rate me.
Thanks again, Ron

Expert:  rpmdiag replied 1 month ago.

Our goal here is to assist you in the repair of your vehicle by
supplying you with well educated information. We may not always
have the exact fix you wanted to hear, but our job is to get you on
the right track, which we always do. We can’t hear, see, smell or
touch your vehicle from where we’re at, so your understanding of
that is greatly appreciated. There are no magical or miraculous
answers, but we do our best to guide you in the right direction.
Thanks, Ron

Expert:  rpmdiag replied 1 month ago.

If you are satisfied with my answer, I would greatly appreciate a 5
star rating now and I will still assist you after you have rated me
too if another question pops up. I don’t get credit for helping you
until you rate me.
Thanks again, Ron