RAM 3500 Truck 2WD V10-8.0L VIN W (1997)
Blower Motor Relay: Testing and Inspection
Blower Motor Relay
Fig 39 Blower Motor Relay Removal/Installation
RELAY TEST
Remove the blower motor relay from its wire harness connector as described to perform the following tests:
1. A relay in the de-energized position should have continuity between terminals 87A and 30, and no continuity between terminals 87 and 30. If OK.
go to Step 2. If not OK, replace the faulty relay
2. Resistance between terminals 85 and 86 (electromagnet) should be 75 +/- 5 ohms. If OK, go to Step 3. If not OK, replace the faulty relay.
3. Connect a battery to terminals 85 and 86. There should now be continuity between terminals 30 and 87, and no continuity between terminals 87A
and 30. If OK, see the Relay Circuit Test procedure. If not OK, replace the faulty relay.
RELAY CIRCUIT TEST
1. The relay common feed terminal cavity (30) is connected to battery voltage and should be hot at all times. If OK go to Step 2. If not OK, repair the
open circuit to the fuse block module as required.
2. The relay normally closed terminal cavity (87A) is connected to terminal 30 in the de-energized position, but is not used for this application. Go to
Step 3.
3. The relay normally open terminal cavity (87) is connected to the blower motor. When the relay is energized, terminal 87 is connected to terminal
30 and provides full battery current to the blower motor. There should be continuity between this cavity and the blower motor relay output circuit
cavity of the blower motor wire harness connector at all times. If OK, go to Step 4. If not OK, repair the open circuit to the blower motor as
required.
4. The coil battery terminal cavity (86) is connected to the electromagnet in the relay. It is energized when the ignition switch is in the On position.
Check for battery voltage at the cavity for relay terminal 86 with the ignition switch in the On position. If OK, go to Step 5. If not OK, repair the
open circuit to the ignition switch through the Power Distribution Center (PDC) as required.
5. The coil ground terminal cavity (85) is connected to ground. This terminal supplies the ground for the relay electromagnetic coil. There should be
continuity between the cavity for relay terminal 85 and a good ground at all times. If not OK, repair the open circuit as required.