What are the differences between the auto and 5 speed wiring harnesses that connect to the gauge cluster? I know the auto tach has a 7k rpm redline and the obvious P,R,N,D,S,L. The reason I ask is my car had an auto to manual swap and I would like to buy the Mazdaspeed gauge cluster and it comes for the manual trans only.

 

The cluster connectors are the same for 5 spd and auto harnesses and the physical instrument harness differences are primarily at the console connectors.
That being said, you might still have conflicts if the connector pin out assignments are different or you might have ECU conflicts since 5 spd and auto ECU's are also different. It might be worth looking at auto vs 5 spd connector pinouts and wiring diagrams before making the purchase.
If Mazdaspeed states their cluster is for 5 spd only, there obviously has to be a very good reason for this. (I don't know from your post what was changed over in your swap.) Does your automatic cluster work with your 5 speed swap?

 

I did a auto to manual swap. Initially I used the auto cluster until my odometer died and then replaced it with a manual without a problem.

 

Sure does. There were also 2 wires that were spliced and grounded.

 

i did the "great gauge cluster how to" and when i did my cluster in my car (still an auto) it had a seperate plug JUST for the PRNDSL lights and auto specific stuff and when i intsalled the manual aftermarket cluster it didnt even have that plug for the cluster in the back, and my stuff works just fine, now the only 2 wires that I added were for the map sensor signal and ground for if your new cluster has a boost gauge in it instead of an oil pressure gauge, otherwise it will be plug and play for sure.