[C320-list] Ideas on engine side electrical problem?

[Christian]

"Has your vented loop on the hose leading into the heat exchanger been
leaking and spitting water"

Yup!  In fact, last spring, I replaced the duck bill  in the siphon hose
due to this!

"On your engine...when you energize the circuit, does the glow plug
automatically start heating up or is that a deferent position on the start
switch."

My problem begins when the console switch is on, not even key in ignition,

I'm going to guess I have corroded connection.  I haven't cleaned
electrical connections before, can this be done and if so, any
solution/chemical suggestions?

As always, you guys are the best.
-Christian