What are the common electrical drain issues in the 2020 Highlander?

Common Electrical Drain Issues in the 2020 Toyota Highlander (Fourth Generation)

The 2020 Toyota Highlander, like many modern vehicles, is equipped with numerous electronic systems that can potentially lead to electrical drain issues. Below are common symptoms, diagnostic steps, tools required, and repair instructions for addressing these issues.

Step 1: Initial Inspection

1. Visual Check: Inspect the battery terminals for corrosion, loose connections, or damage.
2. Battery Condition: Check the battery with a multimeter to ensure it’s fully charged (12.6 volts or higher when the engine is off).

Step 2: Measure Parasitic Draw

1. Tools Required:

   • Digital Multimeter (DMM)
   • Wrench set
   • Battery terminal puller (optional)

2. Procedure:

   • Turn off all accessories and ensure the vehicle is locked.
   • Disconnect the negative battery terminal.
   • Set the multimeter to measure DC amps and connect it in series between the negative battery post and the negative cable.
   • Record the amperage reading. A normal parasitic draw should be around 30 mA or less.

Step 3: Identify the Source of Drain

1. Fuses:

   • Remove fuses one at a time while observing the multimeter readings.
   • When the current reading drops significantly, you have found the circuit causing the drain.

2. System Inspection:

   • Inspect the circuit associated with the fuse identified. Common culprits may include:
     • Interior lights (glove box, trunk lights)
     • Infotainment system
     • Alarm system
     • Aftermarket accessories

Tools Required

• Digital Multimeter (DMM)
• Wrench set
• Fuse puller
• Battery terminal cleaner or wire brush
• Basic socket set
• Screwdrivers (flathead and Phillips)

Repair Instructions

Step 1: Address the Source of the Drain

1. Interior Lights:

   • If the interior lights are failing to turn off, inspect the door switches for proper operation or misalignment.
   • Replace faulty switches if necessary.

2. Infotainment System:

   • If the infotainment system remains powered after the vehicle is off, check for software updates or reset the system.
   • If the problem persists, consider disconnecting the system until further diagnosis.

3. Aftermarket Accessories:

   • Remove any aftermarket installations (like alarms, remote starters) temporarily to check if they are causing the drain.

Step 2: Replace Components if Necessary

• If any components (switches, fuses, battery) are found faulty, replace them with OEM parts to ensure proper function.

Step 3: Reassemble and Test

1. Reconnect the negative battery terminal.
2. Start the vehicle and check all systems for proper operation.
3. Re-measure the parasitic draw to confirm it is within acceptable limits.

Step 4: Preventive Measures

• Regularly check battery health and connections.
• Ensure all electronic systems are turned off when the vehicle is parked.
• Consider installing a battery disconnect switch if the vehicle will be parked for long durations.

Conclusion

If problems persist after following these steps, it may be necessary to consult with a professional technician or Toyota dealership for advanced diagnostics. Electrical issues can sometimes be complex and require specialized equipment for resolution.