Speedo cable on w124s can ONLY be removed by pulling the instrument cluster. But make sure you unclip the cable from the black panel BEFORE pulling the cluster.

True, but OP's talking about a w123. W126's are the same as 124's, with their electric speedo's. (and I don't mean swim suit)

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Geeze squabble I was going to say I can show you how to remove it since I've done it a million times. This thread is kinda old!

My trick is to stick my hand up behind the dash and push it out gently. Then I disconnect the spedo cable. Once that is loose I can easily free everything else!

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