Dodge R1500 1999 Service Manual page 826

Using an ohmmeter, check for continuity between heater control panel
connector terminal No. 7 and terminals No. 3, 4, 5 and 6 while
rotating blower motor switch. See Fig. 2.
5) If continuity does not exist at any terminal, replace
faulty heater control panel. If continuity exists as specified, check
for open in circuits between heater control panel and blower motor
resistor. Also check for an open in circuit between heater control
panel and blower motor.
Fig. 2: Identifying Blower Motor Switch Connector Terminals (Dakota,
Durango & Ram Pickup)
Courtesy of Chrysler Corp.
Ram Van/Wagon
1) Disconnect negative battery cable. Remove heater control
panel. See HEATER CONTROL PANEL R & I. Disconnect heater control panel
harness connector. Using an ohmmeter, check for continuity between
heater control panel C3 harness connector terminal "C" (Black wire)
and ground. See Fig. 4. Go to next step.
2) If continuity exists, go to next step. If continuity does
not exist, repair open in Black wire between heater control panel and
ground connector located at lower right of steering column.
3) Place heater mode control knob to any position except OFF.
Using an ohmmeter, check for continuity between heater control panel
C3 connector terminals "B" (Violet wire) and "C" (Black wire). If
continuity exists, go to next step. If continuity does not exist,
replace faulty heater control panel.
4) Using an ohmmeter, check for continuity between heater
control panel C3 connector terminal "B" (Violet wire) and C1 connector
terminal "E" (Violet wire). See Fig. 3. If continuity exists, go to
next step. If continuity does not exist, repair open in Violet wire
between heater control panel C3 and C1 connectors.
5) Using an ohmmeter, check for continuity between heater
control panel C1 connector terminal "E" and terminals "B", "C" and "D"
while rotating blower motor switch. See Fig. 3.
6) If continuity does not exist at any terminal, replace
faulty heater control panel. If continuity exists as specified, check