Key fob won't turn/start car, lock/unlock doors
Thread Starter
Newbie
Joined: Oct 2018
Posts: 2
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S 430
Key fob won't turn/start car, lock/unlock doors
Ok, I drove about 60 miles this morning. No problems, strange noises, or anything out of the ordinary. Stopped home for about 30 minutes and headed back out the door. Started the car over again, started fine drove around the corner and the festivities began! My entire dash cluster lit up!! Every light or warning was illuminated for about 5 seconds and then the car just died. Put her back in park turned the key to the off position then tried to turn the key again and... Nothing. Now, my key fob will not lock or unlock my doors, but the internal central locking system works fine. All interior lights including my headlights are working as they should. Can access the trunk from the door control, but not the key fob. Interesting thing is my steering wheel isn't locked or in the lock position. I'm able to put the gear shifter into gear rather easily also. I replaced the batteries in the fob, checked a lot of fuses, tested the fob to assure it was working and all to no avail. Me and my 2004 s430 are stumped, and we need some help....
MBWorld Fanatic!
Joined: Dec 2012
Posts: 2,474
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From: Ball Ground, GA (N of Atlanta)
2003 S500 2007 GL450
Pull the floor light located behind the right rear passenger's heels. Remove and check the yellow 20-Amp fuse located near the inboard end of the fuse row. Not likely to be the answer, but the check is quick and free.
Has it been raining? Open the hood and use a good light to look down to the bottom of the HVAC plenum under the black plastic grille. Any trace of water in the plenum is a very bad sign. If the drain is plugged, water will fill the plenum and overflow inside the car under the carpet. There will be no visible water inside the car, but it will cause major electrical issues.
Has it been raining? Open the hood and use a good light to look down to the bottom of the HVAC plenum under the black plastic grille. Any trace of water in the plenum is a very bad sign. If the drain is plugged, water will fill the plenum and overflow inside the car under the carpet. There will be no visible water inside the car, but it will cause major electrical issues.
Thread Starter
Newbie
Joined: Oct 2018
Posts: 2
Likes: 0
S 430
Problem solved
Checked the mentioned fuse and it looked good. I try and make a habit of checking the plastic grille cover as I'm aware of the issues it can cause due to water damage. It's bone dry and clear of any debris. If you come up with any other solutions it'd be greatly appreciated. Thanks for the response.
Update
So, after hours of Google and YouTube searches, phone calls, finally figured it out. Literally just a 7.5 fuse in the cockpit on the passenger side. Apparently (in my opinion) this fuse controls far too many functions including steering wheel lock, heated steering wheel, ignition switch... Appeared as if the box itself was shorting the fuse soon as I put in a new one. Ultimately removed the fuse box itself inspected the wires saw nothing then placed in a new fuse and voila!! Key fob works, steering wheel went back to position and everything functioned as it should. Hope this helps someone else in the future.
Update
So, after hours of Google and YouTube searches, phone calls, finally figured it out. Literally just a 7.5 fuse in the cockpit on the passenger side. Apparently (in my opinion) this fuse controls far too many functions including steering wheel lock, heated steering wheel, ignition switch... Appeared as if the box itself was shorting the fuse soon as I put in a new one. Ultimately removed the fuse box itself inspected the wires saw nothing then placed in a new fuse and voila!! Key fob works, steering wheel went back to position and everything functioned as it should. Hope this helps someone else in the future.
Last edited by Xotk; Oct 23, 2018 at 08:14 PM. Reason: Problem solved
