Toyota Tundra Service Manual: Integration Relay

On-vehicle Inspection

ON-VEHICLE INSPECTION

PROCEDURE

1. PRECAUTION

NOTICE:

After turning the ignition switch off, waiting time may be required before disconnecting the cable from the battery terminal. Therefore, make sure to read the disconnecting the cable from the battery terminal notice before proceeding with work (See page ).

2. DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL

NOTICE:

Some systems need to be initialized after the cable is reconnected (See page ).

3. 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.

4. INSPECT INTEGRATION RELAY (HORN RELAY)

NOTICE:

• 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.
• 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.

(1) Measure the resistance according to the value(s) in the table below.

Standard resistance:

If the result is not as specified, replace the HORN fuse.

(b) Measure the resistance of the horn relay circuit. (1) Measure the resistance according to the value(s) in the table below. Standard resistance: Tester Connection Condition Specified Condition 1A-8 - 1C-1 When battery voltage is not applied between 1A-7 and 1C-1 10 kΩ or higher When battery voltage is applied between 1A-7 and 1C-1 Below 1 Ω If the result is not as specified, replace the integration relay.

5. INSTALL INTEGRATION RELAY (UNIT E)

(a) Connect the 3 connectors.

(b) Install the integration relay to the engine room relay block.

(c) Install the engine room relay block cover.

6. CONNECT CABLE TO NEGATIVE BATTERY TERMINAL

NOTICE:

Some systems need to be initialized after the cable is reconnected (See page ).