Tundra 4WD V8-4.6L (1UR-FE) (2010)
Horn Relay: Testing and Inspection
HORN: INTEGRATION RELAY: ON-VEHICLE INSPECTION
1. DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL
NOTICE:
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Some systems need to be initialized after the cable is reconnected See: Testing and Inspection/Programming and Relearning
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After the ignition switch is turned OFF, the navigation system requires approximately 90 seconds to record various types of
memory and settings. As a result, after turning the ignition switch OFF, wait 90 seconds or more before disconnecting the cable
from the negative (-) battery terminal.
2. REMOVE INTEGRATION RELAY (UNIT E)
(a) Remove the engine room relay block cover.
(b) Using a screwdriver, detach the 2 claws and disconnect the integration relay from the engine room relay block.
HINT
Tape the screwdriver tip before use.
(c) Disconnect the 3 connectors.
3. INSPECT INTEGRATION RELAY (HORN RELAY)
NOTICE:
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Some relays are built into the integration relay (unit E). The integration relay cannot be disassembled. If there is a malfunction in
the circuit of the integration relay, replace the integration relay.
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The internal circuit of the integration relay is as shown in the illustration below. Inspect the integration relay using the following
procedures.
(a) Measure the resistance of the HORN fuse.