Pickup and chassis cab. Gas and Cummins diesel. Key start.
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Which wires give constant, ignition and ground on a 2012 Ram 2500 / 3500?
On a 2012 Ram 2500 / 3500, take constant power from the Yellow/Red wire at the junction connector above the driver kick panel, black 43-pin, pin 3, ignition from the Pink/White wire at the wireless Ignition Node (ignition switch), black 12-pin, pin 3, 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 2012 Ram 2500 / 3500 pickup and 3500 / 4500 / 5500 chassis cab. Constant is at the driver kick panel junction connector, and ignition is at the Wireless Ignition Node behind the key.
We did not find a 2012 sheet beyond a horn wire. The iDatalink guide covers 2010 to 2012 trucks, and the body wires come from 2011 sheets. Our own team has not yet metered these on a 2012 truck, and each row says so.
OBD-II portUnder the driver dash
Best power spotDriver kick panel
System voltage12V
Ignition typeKey
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Where do I get constant, ignition and ground on a 2012 Ram 2500 / 3500?
Take constant, ignition and ground from the same area. On 2010 to 2012 trucks the driver kick panel junction connector and the ignition node on the steering column are within reach of each other.
Option 1 Easiest
Driver kick panel and ignition node
Junction connector above the driver kick panel, and the Wireless Ignition Node behind the key. Key start.
Constant
Yellow/Red
Junction connector above the driver kick panel, black 43-pin, pin 3Always hot, 30A. From installer wire sheets for a 2011 Ram 3500 on the12volt.
Ignition
Pink/White
Wireless Ignition Node (ignition switch), black 12-pin, pin 3Hot in run and start. Some trucks use Pink/Tan. iDatalink lists the same wire for 2010 to 2012.
Ground
Body ground
Body metal under the driver dashClean, bare metal only. Never the battery negative post.
Accessory
Dark Blue/Pink
Cigar lighter, gray 3-pin, pin 1Hot in accessory and run.
Brake is also on the ignition node, pin 8 (White). Never tap the starter for power.
Option 2 Under the hood
At the TIPM
Totally integrated power module, the fuse and relay box in the driver front of the engine bay.
Constant
Red
Battery or TIPM, driver front of the engine bayAlways hot. A second 2011 post gives this instead of the kick panel wire.
Ignition
Not on this plug
Use the ignition node (Option 1)No ignition wire is listed at the TIPM.
Ground
Body ground
Body or frame metalClean, bare metal only.
Run any wire through the firewall with a grommet, and fuse it at the source.
Power wires from installer wire sheets for a 2011 Ram 3500 on the12volt (fetched twice) and the iDatalink guide for 2010 to 2012 trucks. The two 2011 posts give different constant wires, so meter before you tap.
What are the turn signal, reverse and light wires on a 2012 Ram 2500 / 3500?
Circuit
Wire color
Location and what it does
Left turnPositive +Not yet checked
White/Light Blue (front)
White/Dark Green (rear)
Location not given on the 2011 sheetFlashes with the left signal. From installer wire sheets for a 2011 Ram 3500 on the12volt.
Right turnPositive +Not yet checked
White (front)
White/Yellow (rear)
Location not given on the 2011 sheetFlashes with the right signal.
Park lightPositive +Not yet checked
White/Light Green (left)
White/Tan (right)
White (switch)
TIPM brown 40-pin, pin 19 (left); black/red 50-pin, pin 6 (right); White at the park light switchThe White switch wire is a multiplexed signal (iDatalink). Meter before you use it.
HeadlightNot foundNot yet checked
Not found
Not foundWe found no headlight wire for 2010 to 2012.
ReversePositive +Not yet checked
White/Red
TIPM brown 40-pin plug, pin 15Hot in reverse. Same color as the Ram 1500, different pin.
Dome lightPositive +Not yet checked
Yellow/White
Driver A-pillar or instrument cluster, black 10-pin, pin 5Dome output.
Each chip shows the main insulation color with its stripe. Source: 2011 installer sheets on the12volt.
Where are the brake, door, speed and CAN wires on a 2012 Ram 2500 / 3500?
Circuit
Wire color
Location and what it does
BrakePositive +Not yet checked
White
Brake switch, or the ignition node black 12-pin, pin 8Hot with the pedal pressed.
DoorsNegative -Not yet checked
Violet
Violet/White (passenger)
Violet/Gray (left rear)
Violet/Yellow (right rear)
Door switch wires; locations not given on the 2011 sheetViolet is the driver door. iDatalink calls the driver door wire Purple/Gray at the driver kick panel, so meter it.
Parking brakeNegative -Not yet checked
Dark Green/White
Parking brake switch, black 1-pinGrounds with the parking brake set.
Vehicle speedAC signalNot yet checked
Dark Green/Brown
PCM rearward 76-pin plug, pin 69 (diesel, automatic)Speed signal. Same color as the Ram 1500, different pin.
TachAC signalNot yet checked
Dark Blue/Gray (Cummins)
PCM forward gray 76-pin plug, pin 51Engine speed signal on the Cummins diesel. Both 2011 posts agree.
Lock / unlockNot foundNot yet checked
Not found
Not foundWe found no lock wire for 2010 to 2012 HD trucks.
Sources: installer wire sheets for a 2011 Ram 3500 and 3500/5500 on the12volt, and the iDatalink install guide for 2010 to 2012 2500/3500 and 2011 to 2012 4500/5500 trucks. Headlight and lock wires were not found for 2010 to 2012.
Which years share wiring with the 2012 Ram 2500 / 3500?
This page2012iDatalink 2010 to 2012 guide plus 2011 sheets.
Same wiring2010 and 2011The iDatalink guide covers 2010 to 2012 trucks on one page, and the 2011 installer sheets give the body wires. 2010 and 2012 have no year-specific sheet.
Not this page2013 to 2018The 2013 update moved most wires to a new BCM under the dash. Those years have their own pages.
Where are the fuse boxes and ground points on a 2012 Ram 2500 / 3500?
Under the hoodTIPMThe totally integrated power module in the driver front of the engine bay holds the fuses and relays. We did not find a fuse map we trust; check the lid.
UpfitterAux fuse box and feedsWe did not find an upfitter feed table for this year.
Ground pointsClean body metalWe did not find a published ground point for devices. Use clean, bare body metal, never the battery negative post.
Our team has not yet checked the fuse boxes on a truck.
Where is the OBD-II port on a 2012 Ram 2500 / 3500?
OBD II
Diagnostic portOBD-II port: under the driver dashPlug-in GPS trackers and OBD harnesses connect here. Check the port before you plan the install.
Common questions about 2012 Ram 2500 / 3500 wiring
What wire is constant power on a 2012 Ram 2500 / 3500?
Yellow/Red at the junction connector above the driver kick panel, black 43-pin, pin 3. Always hot, 30A. Meter it before you tap it.
What wire is ignition on a 2012 Ram 2500 / 3500?
Pink/White at the wireless Ignition Node (ignition switch), black 12-pin, pin 3. Hot in run and start. Meter it before you tap it.
Where is the reverse wire on a 2012 Ram 2500 / 3500?
White/Red (positive +) at the TIPM brown 40-pin plug, pin 15. Hot in reverse. Meter it before you tap it.
Where is the brake wire on a 2012 Ram 2500 / 3500?
White (positive +) at the brake switch, or the ignition node black 12-pin, pin 8. Hot with the pedal pressed. Meter it before you tap it.
Where is the parking brake wire on a 2012 Ram 2500 / 3500?
Dark Green/White (negative -) at the parking brake switch, black 1-pin. Grounds with the parking brake set. Meter it before you tap it.
Where is the vehicle speed signal on a 2012 Ram 2500 / 3500?
Dark Green/Brown at the PCM rearward 76-pin plug, pin 69 (diesel, automatic). Speed signal. Meter it before you tap it.
Which years share wiring with the 2012 Ram 2500 / 3500?
2010 and 2011. The iDatalink guide covers 2010 to 2012 trucks on one page, and the 2011 installer sheets give the body wires.
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