Clicking Sound Dashboard

[ELDERDADO]

Anyone know what causes the regular clicking sound behind the passenger side dashboard on a'72 Coupe?

["Cadillac Kid" Greg Surfas 15364]

Sounds like a defective AC programmer
Greg Surfas

[TJ Hopland]

Yep.  It will likely change if you change the temp dial or modes.  May not go away but should change.

Why is it doing that?  You have to go through the troubleshooting process to figure out what isn't happy.  Cadillac Tim wrote troubleshooting manuals for these more recently using normal DIY tools and based on what often fails with age vs the factory manuals that were based of factory tools and being fairly new units.

Do you want your system to work or just stop clicking?

[ELDERDADO]

Both would be nice, but I get it. It's old. Like me.
 I click too when I walk. I will try the troubleshoot guides. Thank You.

[TJ Hopland]

I have had mine rigged up for a while but I seem to recall if you turn the dial all the way down to 60 and put the mode to vent that will reduce the clicking. 

Mine has a bad transducer and amplifier and during the testing I discovered a workaround.  There is a vacuum servo down in the programmer which is the control box down on the ductwork on the passenger side.  If you disconnect and plug the vacuum line feeding that and connect a hand vacuum pump/gauge you can manually control the temp and blower speed. 

Here is Tim's site.  Kinda old school but his contact info is there.
https://cadillactim.com/#manuals