I have 2 94 mefi-1 computers from my 502's that are at the machine shop. I just purchased a scan tool and want to check the hours. I have the engine wiring harness and was curious how I can trick it into believing the ignition is on with the wiring harness being on the floor. Any help is appreciated.

Hook up the heavier gauge wires to the + post on a battery. Hook up all grounds to the - post on a battery. Then, put 12V+ power to the purple wire. It will be in a plug that went to the 10 pin harness. In that plug will also be a grey wire, tan/white, blue/white, white, purple, etc. Put power to the purple one and you should here the relays click. It will then be powered up so that you can plug in the scan tool and check the hours.
Eddie