I always had one Mercedes and just bought 96-300d with 234,000.00 all was fine except check engine light, batty seems week so just for a hack of it pored Epsom salt and left it on slow cycle for 12 hours. Asked son to hook it up and car started as usual but the cluster is not working. I bought and put a new battery as old battery was bad and cluster is still not working. I read K40 relay and want to know if its the same for E300 of 96 and if that is the problem and how can I check it. Thanks to all- BN