Does swapping a 97 Honda cluster with a 96-00 LX cluster somehow short the ecu?
 

I thought I'd keep my 97 Honda Civic Cx KA 5MT with 109k miles. I bought another cluster from eBay "Speedometer Cluster Sedan Base LX Fits 96-00 CIVIC 648564" in order to have a tachometer and swapped the odometer from my original cluster into it. When I started it up, the speedometer didn't work at all although the other gauges were just fine. I checked the fuses, they were fine.

1. I took the odometer out and replaced it into the replacement cluster with the tachometer and installed that: still no speedometer, although the other gauges were just fine.

2. I replaced the original odometer back into my original cluster and reinstalled that: still no speedometer, although the other gauges were just fine.

3. I checked the wires at the VSS plug with a multimeter, there was continuity where it should be and the voltage was 5+ in one line and 11+ in the other.

4. I then replaced the speed sensor with a new after market one: still no speedometer, although the other gauges were just fine.

5. I then tested the contacts on the cluster's "B" plug and there was voltage.

6. I cleaned the contacts at the VSS plug.

7. I then tested the gray wire "To speed sensor" from the ecu (through the hole in the fire wall) and there was nothing. Incidentally, that wire broke at the clip and I'll replace it with a tap connector when that arrives.

8. There is also a blue wire that comes through the same hole and goes to the distributor.

9. Assuming that the ecu had gone bad, I ordered another one from eBay and it will be arriving in a couple of days.

My question is: does swapping the clusters somehow short the ecu causing ONLY the speedometers to fail?
Also, the gray wire "To speed sensor" was blackened when I had to cut back the end to replace it into the temporary but working connector. I've read online that this indicates only that the wire has been exposed to high temps and that it is an old wire. In the event that I have to replace that particular wire, what do I use? I've looked at "Honda parts" online but they only identify the components and provide no info on that particular wire. If I replace it with another aftermarket wire, what gauge of wire do I use?

Thank you for your attention.

Re: Does swapping a 97 Honda cluster with a 96-00 LX cluster somehow short the ecu?
 

Nah it wouldn't

If the speed sensor was bad, or the ecu was bad, you would have a check engine light. If the check engine light isnt illuminated then we know the ecu is getting a good speed reading

The ecu and the gauge cluster both are on the same blue wire with a white stripe connected to the speed sensor

More likely you messed up the ribbon that provides the power on the back of the cluster, or you didnt tighten the screws down hard enough. The screws conduct electricity along the back of the cluster on that green circuit ribbon

Re: Does swapping a 97 Honda cluster with a 96-00 LX cluster somehow short the ecu?