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Which wires give constant, ignition and ground on a 2018 Toyota Tundra?
On a 2018 Toyota Tundra, take constant power from the Black wire at the dash fuse box, white 1-pin plug (3F), pin 1, ignition from the Black wire at the ignition switch, white 8-pin plug, pin 6, and ground to clean, bare body metal. Meter every wire first.
Written by API Signal, fleet GPS and camera installers for 35+ years across Georgia, South Carolina and North Carolina, installing every major telematics and camera brand. Every wire on this page lists its source.
Test every wire with a meter before you tap it
No wiring information is ever guaranteed. Colors and locations change with trim, options and build date, and the manufacturer can change them in the middle of a model year. We share this as a starting point for installers, and you are responsible for confirming every connection on the truck in front of you.
This page covers the 2018 Toyota Tundra, the first year with the H-key.
This truck has an H-key. The colors come from a 2018 key-start sheet and a 2021 push-start sheet. No Toyota wiring diagram was available to us, so every color here is installer-reported. Our own team has not yet metered these on a 2018 truck.
OBD-II portUnder the driver dash, white plug above the brake pedal
Best power spotDash fuse box, driver side
System voltage12V
Ignition typeH-key
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Where do I get constant, ignition and ground on a 2018 Toyota Tundra?
Take constant, ignition and ground from the same area.
Option 1 Key start
Key start: ignition switch
Steering column, white 8-pin plug, and the dash fuse box just below it.
Constant
Black
Dash fuse box, white 1-pin plug (3F), pin 1Always hot, 40A. The thick Black wire.
Ignition
Black
Ignition switch, white 8-pin plug, pin 6Hot in run. Light Green on pin 1 is the second ignition wire. iDatalink agrees.
Ground
Body ground
Body metal under the dashClean, bare metal only. Never the battery negative post. No source named a factory ground bolt.
Accessory
Red
Ignition switch, white 8-pin plug, pin 2Hot in accessory and run. Red on the 2018 H-key sheet; older trucks use Gray on this pin, so meter it.
The starter is Green on pin 7. Blue (pin 5) and White (pin 4) are 5A constants only. Never tap the starter.
Option 2 Dash cam
Fuse tap
Dash fuse box under the left side of the dash.
Accessory
Fuse tap
Dash fuse box, power outlet 15A fuse (#27 or #29)For a dash cam. Meter the slot to see whether it is switched.
Ground
Brown
Radio, white 10-pin plug, pin 7Radio ground.
Fuse numbers from a transcription of the 2018 to 2021 owner's manual. Check the lid label first.
Key-start colors from a 2018 Tundra H-key wire sheet on the12volt, with the iDatalink install guide for the 2018 Tundra agreeing on the switch pins.
What are the turn signal, reverse and light wires on a 2018 Toyota Tundra?
Circuit
Wire color
Location and what it does
Left turnPositive +Not yet checked
Black (front)
Yellow (rear)
Front: driver kick, gray 12-pin plug, pin 11. Rear: dash fuse box, white 32-pin plug (3H), pin 8Flashes with the left signal. The 2018 and 2021 sheets agree.
Right turnPositive +Not yet checked
Pink (front)
Green (rear)
Front: passenger kick, white 20-pin plug, pin 11. Rear: dash fuse box 3H, pin 6Flashes with the right signal.
Park lightPositive +Not yet checked
Violet
Dash fuse box, white 32-pin plug (3H), pin 32Park lamp output. Switch side is Light Blue (negative).
HeadlightNegative -Not yet checked
Green
Headlight switch, white 20-pin plug, pin 20 (2018 sheet), or Body ECU, white 30-pin plug, pin 12 (2021 sheet)Headlight switch input.
ReversePositive +Not yet checked
Blue
Passenger kick, white 20-pin plug, pin 20Hot in reverse. The 2021 sheet also gives Yellow at the radio gray 28-pin, pin 28.
Dome lightNegative -Not yet checked
Blue
Interior light switch on the dash, black 12-pin plug, pin 11Dome light supervision.
Each chip shows the main insulation color with its stripe. Source: a 2018 Tundra H-key wire sheet on the12volt and a 2021 Tundra push-start wire sheet on the12volt.
Where are the brake, door, speed and CAN wires on a 2018 Toyota Tundra?
Circuit
Wire color
Location and what it does
BrakePositive +Not yet checked
Tan
Brake switch, white 4-pin plug, pin 1Hot with the pedal pressed. Also Red above the driver kick, white 10-pin plug, pin 6.
DoorsNegative -Not yet checked
Gray (driver)
White (passenger)
Lavender/Red or Red (left rear)
Blue (right rear)
Body ECU white 30-pin pins 6 and 27; dash fuse box white 36-pin (3K) pin 24; rear of dash fuse box white 56-pin (3J) pin 31Each grounds when its door is open. The 2018 sheet says Lavender/Red for the left rear; the 2021 sheet says Red.
Parking brakeNegative -Not yet checked
Tan
Dash fuse box, white 32-pin plug (3H), pin 18Grounds with the parking brake set.
HazardNegative -Not yet checked
Blue
A/C control, black 8-pin plug, pin 1Hazard switch input.
Hood pinNegative -Not yet checked
Red
Body ECU on the dash fuse box, white 30-pin plug, pin 11Grounds with the hood open. Fortin says some 2018 trucks report the hood over CAN instead.
SeatbeltNot foundNot yet checked
Not found
Not foundWe found no source for this wire.
Vehicle speedAC signalNot yet checked
Light Green
Radio: white 28-pin pin 17 (2018 sheet) or gray 28-pin pin 27 (2021 sheet)Speed signal. The two sheets give different pins, so meter it.
TachAC signalNot yet checked
Light Green
OBD port, pin 9Engine speed signal. From the 2018 sheet.
CAN busDataNot yet checked
Blue (high)
White (low)
OBD port, pin 6 and pin 14Also Blue/White at the Body ECU white 30-pin, pins 14 and 13. Never cut or splice them.
Sources: a 2018 Tundra H-key wire sheet on the12volt, a 2021 Tundra push-start wire sheet on the12volt and the iDatalink install guide for the 2018 Tundra. No Toyota wiring diagram was available. Park/neutral and seatbelt were not found.
Which years share wiring with the 2018 Toyota Tundra?
This page2018A sheet for this year exists.
Same wiring2019, 2020 and 2021The 2018 key-start sheet and the 2021 push-start sheet share the same body wires. 2019 and 2020 are carried.
Not this page2017 and olderOlder body layout. The 2022 and newer Tundra is a new truck; we have no wire colors for it yet.
Where are the fuse boxes and ground points on a 2018 Toyota Tundra?
InteriorUnder the left side of the dashCigar lighter and power outlet fuses are 15A (#27 and #29). The Body ECU is attached to this box.
Under the hoodEngine bay fuse boxCheck the lid label for the fuse names.
Ground pointsClean body metalNo named ground point found. Use clean, bare body metal, never the battery negative post.
Fuse list from a transcription of Toyota's 2018 to 2021 owner's manual. Check the lid label before you use a slot.
Where is the OBD-II port on a 2018 Toyota Tundra?
OBD II
Diagnostic portOBD-II port: under the driver dash, white plug above the brake pedalPlug-in GPS trackers and OBD harnesses connect here. Check the port before you plan the install.
Common questions about 2018 Toyota Tundra wiring
What wire is constant power on a 2018 Toyota Tundra?
Black at the dash fuse box, white 1-pin plug (3F), pin 1. Always hot, 40A. Meter it before you tap it.
What wire is ignition on a 2018 Toyota Tundra?
Black at the ignition switch, white 8-pin plug, pin 6. Hot in run. Meter it before you tap it.
Where is the reverse wire on a 2018 Toyota Tundra?
Blue (positive +) at the passenger kick, white 20-pin plug, pin 20. Hot in reverse. Meter it before you tap it.
Where is the brake wire on a 2018 Toyota Tundra?
Tan (positive +) at the brake switch, white 4-pin plug, pin 1. Hot with the pedal pressed. Meter it before you tap it.
Where is the parking brake wire on a 2018 Toyota Tundra?
Tan (negative -) at the dash fuse box, white 32-pin plug (3H), pin 18. Grounds with the parking brake set. Meter it before you tap it.
Where is the vehicle speed signal on a 2018 Toyota Tundra?
Light Green at the radio: white 28-pin pin 17 (2018 sheet) or gray 28-pin pin 27 (2021 sheet). Speed signal. Meter it before you tap it.
Which years share wiring with the 2018 Toyota Tundra?
2019, 2020 and 2021. The 2018 key-start sheet and the 2021 push-start sheet share the same body wires.
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