48RE Internal Wiring Harness 2005, used and ready to install. Fits the 48RE. Ships fast from the USA.
If your 2005 Dodge Ram 2500 or 3500 with the 5.9L Cummins and 48RE automatic is throwing transmission electrical codes, stuck in second gear limp mode, or flashing an intermittent overdrive light after a bump in the road, the problem is often not inside the transmission at all. It is the wiring that runs to it. This is a used, original Mopar transmission wiring harness, part number 56051147AD, pulled from a 2005 Ram Cummins with the 48RE. Note: although this listing is filed under internal harness, the part pictured and described is the vehicle-side transmission harness that runs along the transmission, not the short pigtail inside the pan.
The 48RE is a hydraulic four-speed with electronic overrides. The governor pressure solenoid and sensor control the shift points, the overdrive and converter clutch solenoids sit on the valve body, and speed sensors report input and output speed back to the computer. Every one of those signals passes through this harness. The 2005 model year adds another load: that was the year Dodge replaced the TV cable on diesel 2500 and 3500 Rams with an electric transmission throttle valve actuator (TTVA) bolted to the case, so a 2005 harness also carries the actuator motor and position sensor circuits. Because the harness lives next to a hot exhaust and a vibrating diesel, insulation cracks, connector locks break and pins corrode with age.
Before buying, clear the codes and watch for which circuit returns. Back-probe the suspect circuit at the component and at the computer end with the harness flexed; a reading that drops out while you move the loom points to the wiring, not the solenoid or sensor. If you have a speed sensor code, work through our 48RE speed sensor testing guide first, and for overdrive or lockup complaints use the 48RE solenoid testing steps. If every component tests good and the fault follows harness movement, replacing the harness is the clean repair.
This harness came from a 2005 Dodge Ram Cummins with the 48RE automatic and carries Mopar number 56051147AD (earlier suffixes include 56051147AB and 56051147AC). The 48RE was paired with the 5.9L Cummins in 2003 through 2007 Ram 2500 and 3500 trucks, but wiring changed during that run, most visibly when the TTVA replaced the TV cable for 2005. Match the part number on your original harness tag, compare the connector count and shapes in the photos, or send us your year and VIN before ordering. You can browse the rest of our 48RE parts here.
If the truck stayed in limp mode for a long time or the fluid smells burnt, check the fluid (ATF+4 only) and the valve body as well. A 48RE valve body for 2005-2007 and the ATSG 48RE repair manual, which includes wiring and connector views, are the two items most buyers pair with a harness job. For the bigger picture on what fails in these trucks, read 48RE Cummins transmission problems.
| Fits | 48RE 2005 |
| Part type | Internal Wiring Harness |
| Condition | Used |
| Brand | OEM |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
No. Despite the internal harness label on the listing, this is the transmission wiring harness on the vehicle side, Mopar 56051147AD from a 2005 Ram Cummins. Check the photos against your truck before ordering.
Not guaranteed. The 2005 diesel trucks gained the electric throttle valve actuator, so the transmission wiring changed. Match part number 56051147 and its suffix on your old harness or send us your VIN.
Yes. If the computer loses a solenoid, pressure sensor or speed sensor signal, it can default the 48RE to limp mode. An intermittent break in the wiring is a common cause on older trucks.
On a 2005 or later diesel with the TTVA, hold the key on for at least 30 seconds so the computer initializes the actuator, then clear codes and road test. There is no adjustment on the actuator itself.
ATF+4 only. A harness swap does not require draining fluid, but if the truck ran in limp mode or the fluid is dark, service it with ATF+4 and a new filter.
