Recently bought the car. Drove it a few times locally and had no issues. As we were parking it last time, we noticed a small puff/trail of smoke in interior by the gauges/column. We searched but could not find anything amiss. Took it out today and realized speedometer and odometer aren't working - not sure if related to smoke? From research I tried to do this car has a VSS in tailshaft of the T5, and the signal goes to the ECM then to the speedo (no buffer box and no mechanical speedo cable)

Please confirm test protocol:
1) get a data logger and see if ECM is showing speed output OR put car on jacks and connect to wires and look for AC voltage
2) If either of those tests work fine then problem is wiring between ECM and speedo? Best places/connectors to check? What color wire is it? Any grounds I should be checking too?

Thanks!