Proof of life via 9v battery connected to high and low beam circuits for both head lamps. I gave a brief description of how I bench tested these in the video description:
I wanted to make sure these were functioning and found some useful suggestions regarding bench testing them.
With these head lamps, once the vacuum is compromised the filaments will oxidize and quickly burn out. To preserve the vacuum seal, the original silicone may need a fresh coating around the base of the 3 prong connectors. Before testing, gently clean the head lamp with soapy water, rinse and allow to dry. Next, applying a coat of RTV silicone around the connector bases and allow the silicone to dry. Now we're ready to test these out.
First, identify which of the three prong connectors is the ground. This connector will be connected to both the high and low beam filaments and is visible through the lens. The other two connectors are specific to the high and low beam and will be connected to the positive of the 9 volt battery. Using the ground connector and the negative of the 9 volt battery, close the circuit by connecting the positive post of the 9 volt battery to either the high or low beam connectors. You'll see a dim orange glow if the filaments are still in tact.