Mitsubishi Mc897148 Car Relay 24V Auto Wiper Relay Truck Spare Parts

Truck Spare Parts Wiper Auto Relay for Mitsubishi Mc897148 Car Relay 24V

1.Quick Notice

MC897148 24V wiper relay for Mitsubishi trucks and heavy commercial vehicles. Automatic resetting relay designed for intermittent wiper motor circuits on 24-volt electrical systems. Direct plug-in replacement with standard blade terminals. No wiring harness or socket included. Verify original relay voltage and pin configuration before ordering.

2.Description

The MC897148 24V is a dedicated wiper auto relay engineered for Mitsubishi heavy-duty trucks operating on 24-volt electrical systems. This relay is commonly found in vehicles equipped with 6D16, 6D15, 6D22, and 8DC series engines where the chassis uses dual 12V batteries in series. The relay controls the intermittent wipe function of the front windshield wiper motor on trucks that require higher coil resistance for 24V operation.

The relay body is constructed from flame-retardant PBT plastic rated for continuous operation under engine bay and cabin fuse box conditions. The 24V version uses an extended operating temperature range from -30°C to +95°C to accommodate the higher ambient temperatures found in engine compartments of heavy-duty trucks operating at maximum gross vehicle weight.

Internally, the MC897148 24V contains an electromagnetic coil wound with finer gauge enameled copper wire compared to the 12V version. The higher resistance coil draws approximately half the current of a 12V relay while producing equivalent magnetic force to close the contact arm. When the wiper switch is set to the intermittent position, the coil receives a 24V control signal from the wiper timer module. The coil energizes and closes the silver alloy contact arm, sending battery voltage to the wiper motor for a single wipe cycle.

The contact material is silver tin oxide. This material is specifically selected for 24V DC switching applications because it resists contact welding better than standard silver cadmium oxide. DC circuits are more prone to contact arcing than AC circuits. The silver tin oxide composition extinguishes the arc faster and maintains flat contact surfaces over extended service life. The contact gap is factory calibrated to 0.6 mm for 24V operation.

Five blade terminals extend from the relay base. Terminals are tin-plated brass. Terminal numbering follows Mitsubishi standard configuration. Terminal 30 receives constant 24V battery power from the main power distribution panel. Terminal 85 and 86 connect to the wiper control circuit. Terminal 87 supplies switched 24V output to the wiper motor. Terminal 87a remains unused in this application.

The MC897148 24V is not interchangeable with the 12V version. Installing a 12V relay into a 24V system will burn the coil immediately. Installing a 24V relay into a 12V system will fail to energize because the coil resistance is too high to allow sufficient current flow. Always confirm system voltage before ordering.

This relay is suitable for replacement when the wiper motor operates only in continuous low or high speed but fails to perform intermittent wipe cycles. It also addresses failures where the wiper stops mid-cycle or fails to park correctly at the base of the windshield.

3.Parameter Table

4.Custom Content

Installation notes for MC897148 24V wiper relay. Disconnect battery negative cable before accessing relay panel. Locate original relay using diagram printed on fuse box cover. Pull old relay straight upward. Do not use pliers on relay body. Inspect socket terminals for blue-white corrosion or black burn marks. Clean socket with electrical contact cleaner and small brush. Insert new relay until retention click is felt. Reconnect battery and test intermittent wiper function. Listen for distinct click from relay. Click without wiper movement indicates motor ground fault or wiring break. No click indicates failed switch or timer module. Keep relay away from water spray. Heavy trucks operating in rain require sealed fuse boxes. Do not substitute with 12V version. Do not bypass relay to test motor. Direct bypass bypasses overload protection. Replace relay every three years in logging or construction trucks. High vibration environments accelerate contact wear. Carry spare relay in cab storage compartment. Label spare relay with voltage rating. Do not store relay near battery terminals. Accidental contact shorts internal coil.

5.FAQ (Q&A Format)

Q1: What is the difference between MC897148 12V and 24V versions?

A1: The 24V version has higher coil resistance and uses silver tin oxide contacts. The two versions are not interchangeable. Installing the wrong voltage destroys the relay immediately.

Q2: Which trucks use this 24V wiper relay?

A2: This relay fits Mitsubishi Fuso heavy trucks, Super Great models, and commercial chassis with 6D16, 6D15, 6D22, or 8DC engines operating on 24V electrical systems.

Q3: How can I confirm my truck uses 24V before ordering?

A3: Check battery configuration. Two 12V batteries connected in series indicates 24V system. Check voltage across battery terminals with multimeter. Reading between 25V and 28V confirms 24V system.

Q4: Will this relay work in a 12V truck if I change the socket?

A4: No. The 24V coil requires 24V to energize. A 12V system cannot supply enough voltage to pull the contact arm closed. The wiper will not operate.

Q5: Why does my wiper work in continuous but not intermittent after replacing this relay?

A5: Check the wiper timer module. The MC897148 24V relay responds to signals from the timer. If the timer fails to send pulses, the relay never activates regardless of relay condition.

Q6: What causes contact welding in 24V wiper relays?

A6: Common causes are stalled wiper motor due to ice on windshield, worn motor bearings drawing excessive current, or using a 12V rated relay in a 24V system. The silver tin oxide contacts resist welding better than standard contacts.

Q7: Can I test this relay with a 12V battery?

A7: Testing with 12V will not energize the coil because 12V is below the pull-in voltage. Use a 24V power source for bench testing. Apply 24V across terminals 85 and 86. Listen for click.

Q8: What does terminal 87a do on this relay?

A8: Terminal 87a is not connected in the MC897148 24V application. It remains empty. Some Mitsubishi harnesses leave this socket pin unpopulated.

Q9: How many amps does the wiper motor draw at 24V?

A9: Normal operating current is 4 to 6 amps at 24V. Stall current reaches 15 to 18 amps. The 15-amp continuous rating of this relay provides sufficient margin for normal operation.

Q10: Why does the relay click repeatedly when the wiper switch is off?

A10: Repeated clicking with switch off indicates a short circuit in the wiper switch or timer module sending stray voltage to terminal 85 or 86. Replace the switch or module. The relay is not the cause of this fault.