Technical Information
no.
912-100-0108
page
10/11
status: 14.07.05
Fault
Cause
Remedy
Blowers will not
operate at all speeds
Micro-temperature
fusing (MTS) has
been triggered
Exchange resistor and check the
blower motor for the cause of
functional faults
Free up intake/outlet openings and
exchange resistor
Blower switch
defective
Exchange blower switch
Connecting plug
has become loose
Check plug connection at rear of unit
for proper seating. If not assemble it
correctly
Check connection on blower switch
Check the internal electrical
connection
resistance defective Exchange resistance
relay defective
Exchange relay
Blower only runs in the
maximum speed level
Unit only has one
speed
Install resistor and cable set for multi-
speed versions
Blower only runs at
low and medium
speed
Third speed fuse
defective
Exchange fuse
Blower cannot be
switched off
Short-circuit in cable
or blower switch
Rectify short-circuit, if necessary install
new cable(s) and/or switch.
Blower only operates
at reduced power
Incorrect nominal
voltage
The nominal voltage of the unit and
the vehicle power circuit must agree
Contacts
contaminated
clean plug contacts. Proceed carefully
to avoid
Electrical lines are
underdimensioned
Install recommended cable cross-
section
Heat exchanger
severely
contaminated
Carefully clean avoiding damage
which can lead to leaks.
Warning! Observe safety instructions!