Which wires give constant, ignition and ground on a 2025 Ford F-650 and F-750?
On a 2025 Ford F-650 and F-750, take constant power from the Blue/Red wire at the underhood upfitter connector C201 (16-way), left side of the engine compartment, pin 8, ignition from the Gray wire at the same connector C201, pin 9, and ground to clean, bare body metal. Meter every wire first.
Meter every wire before you tap it. Colors change with trim and build date.
Where do I get constant, ignition and ground on a 2025 Ford F-650 and F-750?
Ford builds customer access wiring into every F-650 and F-750 for upfitters. Use it instead of tapping the truck's own wiring.
Option 1 Easiest
Underhood upfitter connector C201
A 16-way inline connector on the left side of the engine compartment, for upfitter wiring.
Constant
Blue/Red
Underhood upfitter connector C201 (16-way), left side of the engine compartment, pin 8Fuse 27 battery feed.
Ignition
Gray
Same connector C201, pin 9Hot in run, fuse 34 (VPWR3). Ford's PTO drawing in the 2027 book shows this circuit at cavity 16, so meter both.
Ground
New ground
Clean chassis or cab metalFord's upfitter connector has no ground pin. Make a clean ground to bare metal.
The same connector has park brake (pin 1), vehicle speed (pin 10) and park-only (pin 15). Blunt-cut upfitter wires stay in the driver footwell behind the OBD port.
Option 2 Lamps at the rear
Rear body builder connector
At the end of the frame or back of the cab, left frame rail, depending on options.
Park light
Brown
Rear body builder connectorTrailer tow park lamp output.
Ground
White/Orange
Rear body builder connectorTrailer tow return (ground).
Ford's lamp outputs are trailer tow relay outputs. Use them as sense inputs only.
Colors from Ford's 2025 Body Builders Layout Book. Meter every wire before you tap it.
Where are the turn signal, reverse and light wires on a 2025 Ford F-650 and F-750 for advanced 360 multicam and video telematics installs?
Circuit
Wire color
Location and what it does
Left turnPositive +Not yet checked
Yellow
Rear body builder connector A (8-pin), pin 7Trailer tow left stop/turn relay output.
Right turnPositive +Not yet checked
Green
Rear body builder connector A (8-pin), pin 8Trailer tow right stop/turn relay output.
ReversePositive +Not yet checked
Gray/Brown
Rear body builder connector A (8-pin), pin 2Reverse lamp relay. One table in the book prints it as Gray.
BrakePositive +Not yet checked
Yellow/Violet
Rear body builder connector A (8-pin), pin 3Stop lamp relay output.
Brake add-onPositive +Not yet checked
Yellow/Violet
Driver footwellFord's circuit for adding loads to the brake pedal switch.
HeadlightNot foundNot yet checked
Not found
Not foundNot in Ford's customer access circuits.
Each chip shows the main insulation color with its stripe. Source: Ford's 2025 Body Builders Layout Book.
Where are the brake, door, speed and CAN wires on a 2025 Ford F-650 and F-750 for advanced 360 multicam and video telematics installs?
Circuit
Wire color
Location and what it does
Park brakePolarity: meter itNot yet checked
White/Violet
Underhood upfitter connector C201 (16-way), left side of the engine compartment, pin 1Park brake signal. Meter set and released.
Vehicle speedAC signalNot yet checked
Violet/Red (gas)
Underhood upfitter connector C201 (16-way), left side of the engine compartment, pin 10Vehicle speed out. Ford's text calls it Violet/Orange; the 2023 and newer pin table prints Violet/Red on gas and Violet/White on diesel.
Park onlyNegative -Not yet checked
Gray/Brown
Underhood upfitter connector C201 (16-way), left side of the engine compartment, pin 15PCM output when the transmission is in park.
DoorsNot foundNot yet checked
Not found
Not foundNot in Ford's customer access circuits.
CAN busNot foundNot yet checked
Not found
Not foundNot in Ford's customer access circuits.
Sources: Ford's F-650 / F-750 Body Builders Layout Books for 2016, 2018, 2019 and 2021 to 2027 (OEM). Headlight, door and CAN wires are not part of Ford's customer access circuits. No book was found for 2017 or 2020.
Where are the fuse boxes and ground points on a 2025 Ford F-650 and F-750?
FusesCustomer access fusesFuse 27 feeds the Blue/Red constant; fuse 34 feeds the Gray ignition, as Ford lists them.
Ground pointsClean metalFord lists no ground wire with the cab customer access circuits. Ground to bare cab or chassis metal, never a painted surface.
RearTrailer tow returnThe rear body builder connector carries Ford's trailer tow return ground for rear equipment.
Fuses from Ford's 2025 Body Builders Layout Book. Our team has not yet checked them on a truck.
Where is the OBD-II port on a 2025 Ford F-650 and F-750?
OBD II
Diagnostic portOBD-II port: driver footwellPlug-in GPS trackers and OBD harnesses connect here. Check the port before you plan the install.
Which years share wiring with the 2025 Ford F-650 and F-750?
This page2025Ford's 2025 book.
Same layout2021, 2022, 2023, 2024, 2026, 2027Same customer access layout. Rear connector colors change by year, so check the lamp rows.
Not this page2019 and olderCustomer access bundle under the dash instead of the underhood connector. No book was found for 2020.
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This page covers the 2025 Ford F-650 and F-750 medium duty truck. Ford builds customer access wiring into these trucks for body builders, so a GPS or camera can take power and signals without cutting into the truck's own harness.
Every color here comes from Ford's 2025 Body Builders Layout Book, which matches 2024. Our own team has not yet metered these on a 2025 truck, and each row says so.
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.
Common questions about 2025 Ford F-650 and F-750 wiring
What wire is constant power on a 2025 Ford F-650 and F-750?
Blue/Red at the underhood upfitter connector C201 (16-way), left side of the engine compartment, pin 8. Fuse 27 battery feed. Meter it before you tap it.
What wire is ignition on a 2025 Ford F-650 and F-750?
Gray at the same connector C201, pin 9. Hot in run, fuse 34 (VPWR3). Meter it before you tap it.
Where is the reverse wire on a 2025 Ford F-650 and F-750?
Gray/Brown (positive +) at the rear body builder connector A (8-pin), pin 2. Reverse lamp relay. Meter it before you tap it.
Where is the brake wire on a 2025 Ford F-650 and F-750?
Yellow/Violet (positive +) at the rear body builder connector A (8-pin), pin 3. Stop lamp relay output. Meter it before you tap it.
Where is the vehicle speed signal on a 2025 Ford F-650 and F-750?
Violet/Red (gas) at the underhood upfitter connector C201 (16-way), left side of the engine compartment, pin 10. Vehicle speed out. Meter it before you tap it.
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No one has sent photos for the 2025 Ford F-650 and F-750 yet, so yours could be the first. Every photo, wire color and tip we use goes on this page with your name on it, and it saves the next installer time under the dash.
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The plugs, tap points, fuse boxes and ground points. Phone photos are fine.
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Tap "Add yours" at the top of this page. Your tip and your photos go in the same box.
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Compliments of
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