it might be worth taking your gauge cluster out to verify the signal or ground connections there,

I know on my 96 civic some of the electrical connections are via the screws holding spedometer / other gauges into the cluster (which I was baffled by from an engineering / WTF perspective) so it's probably worth the time to take the cluster out and secure it back in place.,

i believe there's also a sweet fully picture-ed how to recently posted in the DIY forum so if you're at all unsure that makes it clear.