Bosch ksu 3921 - Refrigerators

its a relay

this is a fusing code - take it out and see if any build up of toner on the ih cover - remove it if there is. then refit the fuser. Turn machine on holding down the utility key, when comes up with black spot in corner you can relese the utility key. after this a screen will appear after a little while - press the 2 resets (trouble and aes) then switch machine off and on again. use the main switch by tray 1 for this

Could be associated with ice being delivered to the drawer as it is made... Or... Motor not mounted tightly, something against it, foreign objects sitting against fridge.

check door gaskets are in good condition Open and close door quickly Wait for maybe 10seconds and try and open the door . If the gaskets are working there will ne a marked resistance to opening

C - 3921 Fusing sensor a wire breaks detection.To reset :
Turn Off the copier.
Press and keep pressed the Utility key and turn ON copier.
Keep pressed the Utility key when Trouble reset message displayed.
Release the Utility key and press the message.
Turn OFF the copier,wait 1 minutes and turn ON.

Download here
http://vinafix.com/viewthread.php?tid=1175

try this first :
turn your thermostat down first until the fridge stops .
turn the thermostat back up only a quater of the way and wait to see if the fridge turns on and off as usual .
if it does , the thermostat is ok .
if it does not , i believe the thermostat is dead .
in regards to the ice in the fridge part , you maybe have the fridge turned to far up but let me know how you go .

Hook up orange terminal screws to an available port on KSU
Loop lines from the telco to the first six pairs on the C6 then to the KSU trunk ports.

Software must be DR5 on KSIU to support caller ID.

Check the hose or the drain hole in the back of the freezer make sure hose is connect and the drain hole is not plugged

I don''t think so. The 6600 and 67xx series were designed for the "N" Ksu's and work on the 1432 and higher systems. You're probably looking for 64xx and 35xx phones.