Chrysler Town and Country 2003 Owner's Manual page 301

*REAR BLOWER MOTOR INOPERATIVE —
TEST
11 Turn the ignition off.
Reconnect all previously disconnected components.
Connect the DRBIII X10 Scope Probe CH7061 to Channel 1 on the DRBIII .
Select the following from the DRBIII menu: PEP Module Tools; Lab Scope; Live
Data; and Lab Scope.
Press F2 and then press Enter.
Using the left/right arrow keys, set the time to 10ms/Div.
Press F2.
Using the up/down arrow keys, set the voltage range to +20.0v.
Press Enter to move the cursor to Probe.
Using the up/down arrow keys, set the Probe to X10.
Press F2.
Start the engine.
Press the ATC Power switch on.
Set the Rear System switch on the ATC module to the Rear Control position.
Using the X10 Scope Probe, back probe the Rear Blower Motor Control circuit in the
Automatic Temperature Control Module C2 harness connector.
NOTE: The Rear Blower Motor Power Module provides a 10.0 volt signal to
the ATC Module over the Rear Blower Motor Control circuit. The ATC
Module provides a variable duty cycle ground to the 10.0 volt signal based
on input from the Rear Blower switch.
NOTE: When the Rear Blower switch is set to LO speed, the ATC Module
provides a short duty cycle (less time grounding the signal voltage).
NOTE: As higher blower speeds are requested, the ATC Module increases
the duty cycle (more time grounding the signal voltage).
NOTE: When the Rear Blower switch reaches HI speed, the duty cycle
increases to where the signal pattern is almost a flat line (with brief voltage
spikes).
Set the blower switch on the Rear ATC Control panel to LO speed then slowly move
it to HI speed while observing the DRBIII display.
The voltage on the scope patten should cycle from approximately 2.0 volts (duty cycle
on) to 10.0 volts (duty cycle off) for all blower speeds.
The duty cycle pattern should change smoothly as the Rear Blower switch is turned
from LO to HI.
The duty cycle on time should change from approximately 8 ms at LO speed, to 15 ms
at medium speed, and to 25 ms at HI speed.
Does the DRBIII display the voltage range and duty cycle as described above?
Yes → Go To 12
No
AUTOMATIC TEMPERATURE CONTROL
ACTION
→ Replace the Automatic Temperature Control Module in accor-
dance with the Service Information.
With the DRBIII , reset the ATC after repair is complete.
Perform BODY VERIFICATION TEST - VER 1.
Continued
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APPLICABILITY
All