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Pete, Mercedes Mechanic
Category: Mercedes
Satisfied Customers: 27894
Experience:  Over 15 years experience as a Mercedes dealer technician
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C250: , i have a problem with my command. it won't power

Customer Question

hi, i have a problem with my command. it won't power up
Submitted: 2 years ago.
Category: Mercedes
Expert:  Pete replied 2 years ago.
My name is ***** ***** I am a professional here at Just Answer. I noticed that your question was not getting a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.
One common cause is the command unit itself fails internally.I have seen these fail quite a bit in the past before and had to replace it for this issue here.The command will need removed to have the power and ground signals tested at it to make sure they are o.k. and the fault codes checked as well in all computers to see if the command is the cause here needing replaced.I suspect it will as this is most common when it doesn't turn on and all fuses are o.k.
Thanks Pete
Customer: replied 2 years ago.

thanks so much Pete. I have had the command unit taken out and checked. power did not get to the command unit at all. When power was supplied from the double trafficator cable, the unit powered on and worked well. I traced the power supply to fuse 26. the fuse itself is okay but there is no power supply to the fuse 26 port. This is as far as I have gone and this is where i need some help

Expert:  Pete replied 2 years ago.
I apologize for the delay.
Looking at the diagram info the Front SAM control unit is the component that powers up this fuse.This is the fuse panel this fuse plugs into itself.The SAM can fail like this here as I have seen in the past before and requires replacement when it does fail.
From what you have described here with no power to this fuse the SAM itself is at fault and needs replaced and programmed by a Mercedes dealer as their computer is needed for the programming.
Thanks Pete

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