Last year about his time I was having issues with my 1999 slk230 turning over but not starting. After reading several posts, I concluded that checking the K40 would be a good idea. I pulled it and checked the solder joints and the relays and they seemed ok to the eye. I did check the notorious 3 joints in the upper left hand corner under magnification and saw no issue. After several other check I ordered and replaced the K40. The car started right up and ran well all summer into the fall. The car was stored in October. I removed the negative terminal on the battery for the winter. This spring I reconnected the battery and the car started right up. It ran a little rough for a couple of minuted but soon smooth out and I took it out for a spin around the block, approximately 3 miles. Later that month I drove it to an errand and the exhaust pipe flange connection let go under the drivers seat. This was at the same time as coverd-19 stay at home orders happened . I could not get the exhaust fixed until the garage that I use was reopened. 2 weeks ago, May 4 the garage reopened and I made and appointment for May 15. The day before I tried to start the car and it did nothing. Dash lights are all on and nothing seems to dim when I turn the key to the start position. I first checked the battery and it was a little low, 12.34V. I charged it to full,13.4V and still no start. I then remembered the K40. Pulled it out today and checked it, it appears to be good. I have reset the throttle sensor doing the 3 minute drill. Now I'm stumped I may be the K40 but I don't want to replace it just for the sake of replacement. I am attaching a pic of the K40 solder side. Any help will be greatly appreciated.
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