Bad Duplexer Connection

[Sparco]

I have the standard version of the HP LaserJet 4250 which did not come with the JetDirect, Duplexer or the 500 Sheet tray.

I recently purchased the Duplexer kit for it Q2439B, removed the spacer at the back and proceeded to install the duplexer. When the two electronic connectors come into contact with each other and the duplexer is clicked into place the error "Bad Duplexer Connection" Appears. I am using the Right Angled power cord and the duplexer kit is butted up against the printer so the connection looks tight.

I thought it was as simple as this but i must be missing something. I compared this to another 4250DTN at another remote site and the moment you remove the duplexer it knows that it was removed until you reconnect it. I was not able to try this suspect duplexer on the other printer.

Can you please offer help?