Hi, I have a civic dx and originally the car's gauge cluster doesn't come with a tachometer. So I got a poem cluster with a tach from eBay and hooked it up. At first it kind of worked, but it progressively got worse until now it just stops working. So I got another cluster and it doesn't work at all still. What could be the problem here? I read that all civic already come with a rpm harness, so I'm confused here. Anything helps, thank you.