Dodge Truck Wiring Harnesses
Wiring harnesses for Dodge trucks changed significantly from 1961-2006, some years were very nearly identical but many years are one year only. The breakdown is as follows:
1961-1966 Dodge trucks had a fairly simple wiring harness that was point to point without a bulkhead connector.
This was the first year since 1961 the wiring harnesses changed.
1968 truck wiring harnesses were different from both earlier and later years (one year only).
In 1969, a firewall bulkhead connector was introduced. Late in the 1970 model year electronic ignition was introduced.
The 1972 trucks had a firewall bulkhead connector that split into 3 harnesses in the engine compartment and had a fuse box under a small plastic cover behind the glove box lid. Both Points & Electronic Distibutors were offered. 1972-1974 trucks have the same harness layouts, but some of the wires were rearranged in the bulkhead connector and the color codes are different. 1972-1974 instrument clusters have a flat face and are constructed with a metal base.
Big Block and Small Block engine wiring harnesses are the same except for the distributor reluctance pickup connector, which is shorter on the Small Block harness because the distributor is located at the back of the engine.
The 1975 instrument clusters had "wings" added for additional gauges. The wings were also used for aftermarket a/c vents. For the first part of the 1975 model year the cluster had a metal base. The later 1975 models and all of the 1976-1980 models have a plastic instrument cluster base. The 1977 front harness was modified to allow for the parking lights in the grill.
One year only. The underdash and steering column connectors were changed (improved).
The 1979 trucks had a diagnostic connector under an orange plastic cover in the engine compartment.
The 1981 wiring harness had a one-piece connector in the engine compartment that was screw attached to the firewall bulkhead connector. From 1981-1985 the engine computer was attached to the air cleaner.
1981-1993 49 state trucks and Canadian vehicles sometimes did not have computers.
The 1985-1993 trucks had their computer located on the driver's side front fender behind the battery. 1985-1990 360 4BBL engine trucks used two ECU's and no computer. The wiring harnesses for computerized and non computerized trucks are totally different. 1985 and newer 4WD trucks had an added wire going to the vacuum controlled front hubs.
Early 1985 trucks had wide flat pins in their wiring harnesses, late trucks used a much narrower pin.
In 1986-1989 the instrument cluster had an added wire for a speed sensor.
Before TBI was introduced in 1988, the correct wiring harness was a lot easier to identify by application (engine size, transmission type, air conditioning or not etc). From 1988 on, you really need the wiring harness part number.
1988-1990 trucks had the wiper switch on the steering column.
1989-1993 trucks came with electric speedometers.
1989 and 1990 dash wiring harnesses are the same.
1990 and newer had rear anti-lock brakes standard.
1989-1991 Diesel (Early)
Intercooled and non-intercooled trucks had different wiring harnesses. Manual and automatic transmission trucks had different harnesses.
1989-1993 diesel trucks require a specific part number for their computer because there were so many variations.
The steering column wiring went right up into the igniton switch. 1991-1993 trucks also had a different wiper switch. In 1991 they changed the dash wiring harness.
1991 (Late)-1993 Diesel
Manual and automatic transmission trucks had different wiring harnesses.
On 1994 and newer Dodge trucks, there are so many variations of wiring harnesses that having a part number becomes critical. If you can't find a part number for the wiring harness you need because it has been removed or the vehicle has had a fire, you can ask the parts department of your Dodge dealer for it. You will need the last 9 digits of the vehicle's VIN for the dealer to be able to check. The wiring harness part number on 1994-2002 2500 and 3500 models and 1994-2001 1500 models is on the side of the fuse box. The computer is in the engine compartment on the passenger side of the firewall. The wiring harness breaks down into 5 components:
1. The engine harness supplies connections to the alternator, fuel injection and distributor. The part number is on a tag near the brake booster.
2. The front harness supplies connections to the headlights, parking lights, and front ABS sensors. The fuse box and the front harness are hardwired together. The part number is on the side of the fuse box.
3. The frame harness disconnects under the drivers side front wheel well behind the inner fender. It supplies connections to the fuel tank, tail lights, brake lights and rear brake ABS sensor.
4. The under dash harness connects the instrument cluster, steering columns, ignition and radio.
5. The body harness attaches to the body computer, power seats, rear dome light and seat belts.
Some 1994 trucks had front ABS brakes. If there is an electric wire attached to the flexible hydraulic brake hose, the vehicle has ABS brakes. If there is no wire, the vehicle does not have front ABS brakes.
1994 and 1995 V10 engine trucks have an ignition module located on the passenger side front fender behind the washer fluid reservoir.
The instrument cluster on 1994-97 Dodge trucks can be disassembled and parts replaced.
The computers really became important for diagnostic code retrieval from 1994 and newer.
The computer on 1994-2006 Dodge trucks is in the engine compartment on the passenger side of the firewall. On 1994-95 trucks it was encased in a black plastic cover.
1996 and 1997 wiring harnesses had lots of small differences. 1996-2006 computers are in a sliver box.
In 1998 and newer, the computer started telling the transmission when to shift.
On 1998-2002 2500 and 3500 models and 1998-2001 1500 models the cluster can't be taken apart.
1998 instrument clusters that have a black plug in the back are a different part number than the ones with a white plug.
Dodge diesel trucks 1998 and newer introduced an engine computer with the 24 valve engine. The 12 valve and 24 valve engine wiring harnesses are very different. There was also a harness difference between manual and automatic transmissions.
Every harness must be identified by a part number. Many variations were used.
2000 used different computers.
The wires were rearranged for the 2001 model year.
On 2002-2006 1500 models and 2003-2006 2500 and 3500 models Dodge trucks, the fuse box is located in the engine compartment on the driver's side front fender at about the midpoint. The fuse box is a separate part with its own part number. The wiring harnesses all plug in to the fuse box. There are 4 main harnesses:
3. Body computer
4. Front end - plugs into dash harness under the dash
The under-hood harness is pretty much one piece.
On 2002-2006 Dodge trucks you have to have the part number to replace the cluster because of the keyless entry feature.
On 2002-2006 trucks you need the steering column part number to replace the steering column.
2002 and 2003 steering columns that have the same features are identical.
2004 and 2005 steering columns that have the same features are identical.
There are significant wiring harness differences between the 2005 and 2006 trucks.
This information should be used as a guide and does not imply the years grouped together are identical. However, they are similar, which can be handy for troubleshooting purposes. The best way to purchase a wiring harness is by the part number, which is usually on a tape or tag near the fuse block. There are many flavors of wiring harnesses for some applications and a one wire change was often all it took to generate a different part number.
Information provided by Marv Neel and Rick Dowden 4-07
Joe Leonard 2007-04-10