2020 Toyota Highlander Fuse Box Diagram & Amperage Guide
An ASE Master Tech’s guide to the 2020 Toyota Highlander's fuse box locations, amp ratings, and protected circuits.
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Welcome to Repairius! I’m an ASE-certified master technician, and today we’re looking at the electrical nerve center of the 2020 Toyota Highlander. Whether your radio just cut out, your 12V power outlet stopped charging your phone, or your headlights went dark, checking the fuses is always the first diagnostic step.
This guide breaks down the fuse box locations, relay locations, and the exact fuse numbers and amp ratings for common circuits on your 2020 Toyota Highlander.
Disclaimer: Fuse layouts can vary slightly depending on your exact trim level (L, LE, XLE, Limited, Platinum) and whether you have the V6 or the Hybrid powertrain. Always verify with the printed legend on the inside of your fuse box lid before pulling or replacing a fuse.
Quick Answer: 2020 Toyota Highlander Fuse Box Locations
The 2020 Toyota Highlander has two primary fuse box locations that handle all of the major electrical components:
- Engine Compartment Fuse Box: Located under the hood on the driver’s side, near the battery. This box handles high-draw components like the ABS, cooling fans, headlights, and engine management (ECM).
- Passenger Compartment Fuse Box: Located under the dashboard on the driver’s side kick panel area. You will need to look up under the dash, above where your left foot rests, to see the plastic cover. This box protects interior electronics like the radio, 12V outlets, blower motor, and airbags.
Engine Compartment Fuse Box
The under-hood fuse box houses both standard blade fuses, cartridge-style fuses for higher amperages, and major system relays (like the Starter Relay, EFI Relay, and Horn Relay). Remove the plastic cover by pressing the side tabs.
Here is a diagram reference for the most critical circuits located in the engine bay:
| Fuse # | Amp | Color | Circuit / Component Protected |
|---|---|---|---|
| 1 | 10A | Red | H-LP RH (Passenger side headlight - High/Low) |
| 2 | 10A | Red | H-LP LH (Driver side headlight - High/Low) |
| 5 | 20A | Yellow | EFI NO.1 (Electronic Fuel Injection / ECM / PCM) |
| 7 | 15A | Blue | IG2 (Ignition system) |
| 11 | 25A | Clear/White | TOWING (Trailer brake / Tow package control) |
| 14 | 15A | Blue | HORN (Dual horns) |
| 21 | 20A | Yellow | FUEL PUMP (Main fuel pump relay/circuit) |
| 25 | 30A | Green | ABS NO.1 (Anti-lock Brake System module) |
| 26 | 50A | Red (Cart.) | ABS NO.2 (Anti-lock Brake System pump motor) |
| 30 | 50A | Red (Cart.) | HTR (Blower motor / Climate control main power) |
| 35 | 10A | Red | A/C (Air conditioning clutch relay) |
| 42 | 30A | Green | ST (Starter motor relay circuit) |
Relay Note: The main relays for the Starter, Fuel Pump, EFI (Electronic Fuel Injection), and Cooling Fans are integrated into this block. If a system is getting power through the fuse but still not operating, swap the relay with a known good one of the same part number to test it.
Passenger Compartment Fuse Box (Under Dash)
The interior fuse box protects the cabin electronics. To access it, crouch down by the driver’s side floorboard and look up under the dash panel. Pop the rectangular cover off to reveal the fuses.
| Fuse # | Amp | Color | Circuit / Component Protected |
|---|---|---|---|
| 1 | 15A | Blue | P/OUTLET NO.1 (12V Cigar lighter / front power outlet) |
| 2 | 15A | Blue | P/OUTLET NO.2 (Rear cargo/console 12V power outlet) |
| 4 | 7.5A | Brown | ACC (Accessory power / Mirrors / Steering wheel controls) |
| 7 | 15A | Blue | RADIO (Infotainment display / Audio system) |
| 9 | 10A | Red | STOP (Brake lights) |
| 12 | 7.5A | Brown | ECU-IG NO.1 (Airbag system / Occupant detection) |
| 15 | 10A | Red | TAIL (Tail lights, Parking lights, License plate lights) |
| 22 | 20A | Yellow | WIPER (Front windshield wipers) |
| 24 | 15A | Blue | SEAT HTR (Heated seats) |
How to Test a Fuse
As a technician, I see a lot of people replace parts without realizing a $2 fuse was the actual culprit. Here is the best way to test your Highlander’s fuses:
- Visual Inspection: Pull the suspected fuse using the plastic puller tool located inside the engine compartment fuse box cover. Hold it up to the light. If the metal "U" or "S" shaped wire inside the colored plastic is broken or scorched black, the fuse is blown.
- Using a Test Light (Preferred Method): You don’t even need to pull the fuse for this. Turn the ignition to the "ON" position. Clamp the ground wire of your 12V test light to a bare metal bolt under the dash. Touch the probe to the tiny metal test points on the top of the fuse. If the test light illuminates on one side of the fuse but not the other, the fuse is blown.
- Using a Multimeter: Set your multimeter to the continuity setting (the one that beeps). Touch the probes to both test points on the top of the fuse. A continuous beep means the fuse is good. No beep means it’s blown.
Common Blown Fuses on this Vehicle
If you drive a 2020 Toyota Highlander, keep an eye out for these commonly blown circuits:
- P/OUTLET (15A): The 12V cigar lighter outlets blow very easily. If your phone charger has a short in it, or if a kid drops a penny into the open socket, this fuse will pop instantly. Always check the socket for debris before replacing the fuse.
- TOWING (25A): If you use your Highlander to tow, trailer wiring is notoriously problematic. A short in your trailer’s wiring harness will immediately pop the towing fuse under the hood to protect the vehicle. If you lose trailer lights or trailer brakes, check the trailer wiring first, then replace this fuse.
- TAIL (10A): This fuse controls the tail lights and parking lights. It often blows if an aftermarket bulb is installed incorrectly or if water gets into the rear light assemblies.
Remember, a fuse blows for a reason—it is the sacrificial lamb protecting your expensive wiring harness from melting. If you replace a fuse and it blows again immediately, do not put a higher amperage fuse in its place! This is a major fire hazard. You have a short circuit that needs to be diagnosed.
If you have a persistent electrical issue that keeps popping fuses, or if a vital system like your ECM or ABS isn't communicating, it's time to bring in a professional.
Find a trusted shop on Repairius.
Before you pull a fuse on the 2020 Toyota Highlander
- Use the label printed on the panel cover or the owner's manual for your exact build. Layouts change with options, model year and build date, so a chart for another truck can be wrong.
- Replace a blown fuse only with the same amp rating. A larger fuse can let wiring overheat.
- A fuse that blows again right away means a short or failing component downstream. Find the cause before replacing it again.
- A good fuse doesn't prove the circuit works — relays, grounds and connectors fail too.
- Disconnect the battery before working near high-current fuses or cables.
Learn more: How fuses, relays and truck electrical systems work
More specs for the 2020 Toyota Highlander
Oil Capacity & Filter
Capacity, weight, filter PN, drain plug torque, change interval.
Fluid Type Specs
Engine oil, coolant, ATF, diff, brake, PS, DEF — with OEM spec numbers.
Coolant Capacity & Type
Total system capacity, OEM coolant spec, flush interval, bleed tips.
Transmission Fluid & Service
Trans model, fluid spec, capacity, filter PN, service interval.
Torque Specifications
Lug nuts, drain plug, caliper, axle nut, plug, key fasteners.
Brake Pad & Rotor Specs
Pad PNs, rotor size, min thickness, caliper torque.
Tire Size & Pressure
OEM size, cold psi, bolt pattern, wheel size, TPMS.
Battery Size & Group
Group size, CCA, AGM/flooded, dimensions, reset note.
A/C Refrigerant & Oil
R-134a or R-1234yf, charge oz, PAG oil spec.
Bulb Sizes (Headlight, Tail, Fog)
Headlight, fog, tail, turn, reverse, interior.
Factory Maintenance Schedule
Service intervals by mileage, severe-duty notes, known issues.
Towing Capacity & Payload
Max tow, payload, GVWR/GCWR, hitch class by trim.
Serpentine Belt Routing & Length
Belt routing, length, rib count, OEM + aftermarket PNs.
Wheel Alignment Specifications
Camber, caster, toe ranges (front & rear), adjustability notes.
Paint Color Codes
All factory colors with paint codes, sticker location, touch-up tips.
Wiper Blade Sizes
Driver/passenger/rear blade size, attachment, OEM + cross-refs.
Spark Plug Type & Gap
Plug PN, gap, torque, interval by engine.
Transmission & Axle Gear Ratios
Trans gear ratios, axle ratios, RPO codes, tow vs MPG impact.
Key Fob Programming
DIY programming steps, FCC ID, fob PN, battery, transponder.
Same spec — other model years
Maintenance & repair guides
2020 Toyota Highlander Maintenance Schedule →
Available maintenance guidance; confirm the manufacturer schedule.
Repair planning references →
Plan the scope of work; detailed procedures need configuration-matched evidence.
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