High/Low vacuum on annunciator panel doesn't work

[sfmse]

I have a '90 MSE with the OEM annunciator panel.  I don't remember the last time I saw the high/low vacuum light either flashing or solid.  I had the annunciator panel overhauled a few years back with no change.  Recently, I checked the vacuum switch on the back of the attitude indicator and found that it was working correctly.  The wires from the vacuum switch (3 wires) go into a cannon plug.  The first indication of an issue was that the mating cannon plug only had two wires coming out of it.  After tracing that side of the cannon plug, I found that those two wires had been cut and capped.  A while back I had a major avionics upgrade done that removed the RNAV system (KNS-81) and installed a Garmin 430W.  I'm thinking that the cannon plug with the two wires was actually the connection for the "remote RNAV" indicator on the annunciator panel which was cut and  capped when the KNS-81 was removed.  I've looked everywhere for the correct cannon plug with 3 wires that match the one coming from the vacuum switch without success.  I'm ready to give up and wire up a new cannon plug from the annunciator panel d-sub connector to get the high/low vacuum light to work. 

The problem I have is that I have wiring diagrams for serial numbers near mine but not one covering my serial number (24-3191).  From the wiring diagram I have for s/n 24-3271 thru 24-TBA, it looks like pin 20 on the annunciator panel d-sub connector is the low vacuum connector, pin 1 is high vacuum and pin 4 is labeled "28 VDC TESR".  Can anyone confirm that those are the same pins for my aircraft (s/n 3191)?  Also, the "28 VDC TESR" pin looks like the supply for the vacuum switch as the high/low vacuum circuitry in the annunciator panel is driven by a 28 vdc input (switched by the vacuum switch to the low vac pin, high vac pin, or no connection).  Can anyone verify that?

Thanks.

Kevin

[Mooneymite]

Wow!  for your first post, that was pretty technical.

I admire your trouble shooting skills.  However, I think you'll find that Mooney wiring diagrams can be pretty elusive. Even Mooney had trouble verifying a portion of my wiring since there were multiple changes about the time mine was built.  Perhaps Mooney did a better job by the time it built yours?

Welcome to MS.

[Guest]

Unfortunately Mooney wiring diagrams are one page for the entire electrical system for your vintage.  If you call tech support at Mooney they may be able to email you the one for your serial range.  From there take it to a blue print printing shop and have it printed in large a workable size.

Clarence

[carusoam]

Welcome aboard, Kevin.

If you haven't done so already, check the test button on the annunciator panel.  To see if this lights the vac lights...

It may be lighting the lights, but the other wires are missing, giving a misleading situation...?

My recent studies of the annuciator panel were to try and identify how the low level fuel lights work.  A test button press after start-up is required for these lights to work.  Quirks of the design...

Good luck with your search...

Best regards,

-a-