Sprinter 2500 L5-2.7L DSL Turbo (2003)
Micro ISO Relay: Testing and Inspection
RELAY
1. Remove the relay from its mounting location.
2. 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 3. If not OK, replace the faulty relay.
3. Resistance between terminals 85 and 86 (electromagnet) should be 60.7 - 80.3 ohms. If OK, go to Step 4. If not OK, replace the faulty relay.
4. 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, perform the Relay Circuit Test that follows. If not OK, replace the faulty relay.
RELAY CIRCUIT TEST
1. The relay common feed terminal cavity (30) of the fuse block is connected to battery voltage and should be hot at all times. Check for battery
voltage at the fused B(+) circuit cavity in the fuse block receptacle for the relay. If OK, go to Step 2. If not OK, repair the fused B(+) circuit to the
fuse block fuse as required.
2. The relay normally closed terminal (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 (87) is connected to the common feed terminal (30) in the energized position. This terminal supplies battery
voltage to the fused B(+) fuse in the fuse block that feeds the accessory when the relay is energized by the ignition switch. There should be
continuity between the fuse block cavity for relay terminal 87 and the fused B(+) fuse in the fuse block at all times. If OK, go to Step 4. If not OK,
repair the open fused B(+) circuit to the fuse block fuse as required.
4. The coil ground terminal (85) is connected to the electromagnet in the relay. It receives battery feed to energize the relay when the ignition switch
is in the Accessory or Run positions. Turn the ignition switch to the On position. Check for battery voltage at the fused ignition switch output
(acc/run) circuit cavity for relay terminal 85 in the fuse block receptacle for the relay. If OK, go to Step 5. If not OK, repair the open fused ignition
switch output (acc/run) circuit to the ignition switch as required.
5. The coil battery terminal (86) is connected to the electromagnet in the relay. The fuse block cavity for this terminal should have continuity to
ground at all times. If not OK, repair the open ground circuit to ground as required.
