Programmer Question

[Chris Kennedy]

I was recently looking at a used heater/ac programmer assembly for an '89, and noticed that towards the top of the unit there is some sort of electronic device which screws into the outer case. I can't find this device on any diagrams of the unit, and was wondering whether anyone knows what this is? The reason I ask is that I bought a new programmer unit recently, and want to change this "whatever it is" if possible, before I install the new unit.

Thanks,

/s/ Chris Kennedy