Engine doesn’t turn over at all, the dash lights come on, dim as normal but the engine doesn’t crank/turn over.

If I connect the positive battery terminal to the middle pin on the harness in the engine bay it turns over but doesn’t start as per this thread:


https://forums.mercedesclub.org.uk/index.php?threads/w124-starting-troubles-probably-not-battery.157041/

If I try to connect the small terminal to the large terminal on the other side of the engine bay it doesn’t turn over at all.