Fault Code Guide

Recirculation Door Actuator Circuit Tests
Test Conditions Test Point
Good
Result
What to Do if Test Fails
actuator
position sensor
feedback signal
circuit
key on, engine off
all connectors connected
Backprobe pins A11 and B5
at control head connector.
0.8V
(recirc.
on) to
4.7V
(recirc.
off)
Check wiring between control
head and recirculation door
actuator.
†
If wiring is okay, replace the
actuator.
†
*
The voltage should be approximately the same as the battery voltage.
†
It is assumed that reference voltage and ground circuits are functioning.
Table 5, Recirculation Door Actuator Circuit Tests
Blower Motor Circuit Tests
The blower motor power and ground are supplied
directly to the blower motor assembly. The blower
speed is controlled by the fan switch on the control
head (climate control panel). The control head sends
a pulse width modulated (PWM) signal to the blower
motor. The frequency of this signal is 2000 Hz. The
pulse width varies with the fan switch selection.
The protection modes for the blower motor are as
follows:
• Reverse Voltage Protection—The motor will not
operate if the polarity of the motor leads, cir-
cuits 98F and ground, are reversed.
• Current Protection—If the motor exceeds the
maximum limit, the speed will be reduced until
the current is within the limits (23.5A maxi-
mum).
• Temperature Protection—If the motor’s internal
temperature sensor senses that the tempera-
ture is too high, the blower speed is reduced to
1000 rpm to reduce the load on the motor and
a comparison is made between the sensor
reading and the maximum limit. If the tempera-
ture is still too high, the blower speed is further
reduced to the minimum value of approxi-
mately 500 rpm and a temperature comparison
is made to the maximum. If, after the second
comparison, the temperature is still too high,
the motor will shut down until it has cooled
sufficiently.
Perform the tests in Table 6 in the sequence pre-
sented. The directions under the column "What to Do
if Test Fails" are sometimes dependent on good re-
sults from previous tests. If any of the tests fail, stop
and perform the specified repair or check. If the
blower motor passes the tests in Table 6 and the
blower still does not operate properly, check the
blower motor. To quickly check for normal operation,
set the fan switch to high and listen for a change in
the sound of the blower near the HVAC unit while
pressing the recirculation button on and off. The
blower will be louder when recirculation is enabled.
Blower Motor Circuit Tests
Test Conditions Test Point
Good
Result
What to Do if Test Fails
main power to
blower motor
battery switch on (if equipped)
key off
blower motor connector removed
Measure between pin 4 of
blower motor connector and
negative battery post.
12V
*
Check fuse F2 in the PDM
under the hood. If the fuse is
blown, check for shorted
wiring or a damaged blower
motor.
Check for an open in circuit
98F.
Cab Heater and Air Conditioner, Valeo 83.00
Troubleshooting
Business Class M2 Workshop Manual, Supplement 13, March 2008300/12