I have been trying to replace the old thermostat with a new digital honeywel thermostat for my trane XL1200. I hooked up the new thermostat like the old one...only 4 wires were available and I used the same color codes. It works ok, but when the t-stat turns on/off there is a loud "click click" noise. Loud enough to wake you up at night..

So, I returned the t-stat and bought a new one and get the same result. a loud click-click.

My question is, could something be wired wrong which is causing the t-stat to get damaged an "click" louder than normal when turning on/off??

When checking the wiring outside, only 4 wires are used there.

yellow - yellow wire (Y)
green - black wire(G)
white to 2 brown wires(w1/w2)
red to red(R)

from thermostat not hooked up are:
orange, blue, and black wires

from the trane the blue wire is not hooked up.

should I hook the blue(B) trane connection up to the blue wire from the thermostat??

now that I have a new thermostat should I "un jumper" w1/w2 browns and run them seperately?

my real issue is fixing the "click" noise...

thanks,