02 f350 7.3 issue
 

Welcome to the site..

If the IDM relay is clicking, the IDM relay gets its relay magnetic coil voltage for closing it’s contacts through the ‘closed’ PCM relay. The IDM, PCM relays are closing controlled by the PCM grounding/controlling of both the relays coil grounds.

So,, kind of a flow chart.....

When the Ignition Switch is cycled to start/run it feeds voltage to the PCM Power Relay (coil side),, the PCM relay coil ground goes through the PCM Power Diode and terminates to chassis/ground completing the circuit and should close the PCM Power relays contacts...
Once the PCM relays contacts are then closed,, voltage then flows trough the closed contacts to the Fuel Pump Relay and IDM relays (coil sides) with the PCM grounding their coils causing their contacts to then close and flow voltage to the IDM itself, as well as the Fuel Pump..

So,, being the engine was out, I’d be suspect of an issue caused by the work,, possibly the PCM grounds located L/side near the firewall (2), and/or you could trouble check for a diagnostic direction to go like an Ignition Switch intermittent drop out to the PCM Power relay, to prove it out and take it and the ignition off the table, also making sure the PCM Power diode is seated/tight etc.. As well as check the IDM relay input feed to confirm Y/N for drop out there for voltage off the PCM relay.. If you have a simple test light, you can check the relays live feeds with a test wire installed. Doubt it would be a bulk head connector etc, and even if so, the relays shouldn’t click unless there’s a voltage dropout inline, missing/intermittent ground etc...

Thanks for the update, glad it was an easier fix...