Mercedes Repair Questions? Ask a Mechanic for Answers ASAP
Fuse #9 in the fuse box at the end of the dash is for the brake lights. Check that fuse and see if it is blown. If the fuse is good there may be a fault with the new brake light switch or there may be a fault with the stop lamp suppression relay. The signal from the brake light switch most pass through the relay before it gets to the brake lights and the traction control module. If the fuse is blown or there is a problem with the new switch or the wiring or the relay you will have no brake lights and the ABS/BAS warning lights will be on. The relay is located in the fuse box under the hood. I've attached a picture below.
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