electrical

Battery Cables - Both

for 2007 Ram 3500 5.9L I6 Cummins · 4WD

Difficulty

Moderate

Time

1.8 h

Tools

Steps

✓Fact-checked. Built from OLP's spec database, then independently fact-checked line by line with every correction applied. Master-tech sign-off by Chris Hackleman is queued. Cross-check torque values against the factory manual, and stop if anything looks unsafe. How our data is made.

This procedure covers the replacement of both positive and negative battery cables on a 2007 Ram 3500 with the 5.9L Cummins diesel engine, including removal of the dual batteries and all cable connections.

Warnings

⚠️Always disconnect negative battery terminals first to prevent short circuits. This vehicle has dual batteries - disconnect both negative terminals before proceeding.

⚠Battery acid is corrosive. Avoid contact with skin, eyes, and clothing. Neutralize any spills with baking soda solution.

⚠The positive cable connects directly to the starter motor. Ensure all connections are tight to prevent voltage drop and starting issues.

ℹ️Radio presets and electronic memory settings will be lost. Note any important settings before disconnecting batteries.

Tools required

10mm socket and ratchetEssential

13mm socket and ratchetEssential

Battery terminal puller

Wire brushEssential

Battery terminal cleaning tool

Baking soda and water solution

Torque wrench

Dielectric grease

Safety glassesEssential

Nitrile gloves

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Parts

Positive battery cable assembly × 1 — Use OEM specification - includes connections to both batteries and starter
Negative battery cable assembly × 1 — Use OEM specification - includes ground connections

As an Amazon Associate and Autel/ANCEL partner, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.

Preparation

Ensure the engine is off and the key is removed from the ignition
Open the hood and secure with prop rod
Identify both batteries - this vehicle uses a dual battery setup located in the engine bay on the driver's side
Take photos of cable routing and connections for reference during reassembly
Clean any heavy corrosion from battery terminals before removal to prevent debris from falling into engine bay

Procedure

1
Disconnect negative battery cables
Using the appropriate socket (typically 8mm or 10mm), loosen the negative terminal clamp bolts on both batteries. Remove the negative cables from both battery posts. Keep the cables away from the battery posts during the entire procedure. The negative terminal is marked with a minus (-) sign and typically has a black cable.
2
Disconnect positive battery cables
Using a 10mm socket, loosen the positive terminal clamp bolts on both batteries. Remove the positive cables from both battery posts. The positive terminal is marked with a plus (+) sign and typically has a red cable or cover.
3
Remove battery hold-down clamps
Using a 13mm socket, remove the battery hold-down clamp bolts from both batteries. Remove the hold-down clamps and set aside. Carefully lift both batteries out of the battery tray and set in a safe location. Note the orientation of each battery for proper reinstallation.
4
Trace and disconnect positive cable at starter
Locate where the positive battery cable connects to the starter motor, mounted low on the driver's side of the engine block. Using the appropriate socket, remove the nut securing the positive cable terminal to the starter solenoid post. Remove the cable terminal and any other wiring connected at this junction. Note the order of any stacked terminals.
⚠Multiple wires may be stacked on the starter post. Document their order for proper reassembly.
5
Remove positive cable routing clips
Follow the positive battery cable from the batteries to the starter, removing any cable clips, ties, or retainers securing the cable to the engine or frame. Note the routing path for proper installation of the new cable.
6
Remove complete positive cable assembly
Once all connections and clips are removed, carefully remove the entire positive battery cable assembly from the vehicle. This cable connects both batteries together and runs to the starter.
7
Disconnect negative cable ground connections
Trace the negative battery cable to its ground points on the engine block and frame. Using a 13mm socket, remove the bolts securing the negative cable terminals to the engine block and chassis ground points. There are typically multiple ground connections - remove all of them.
8
Remove negative cable routing clips
Remove any cable clips, ties, or retainers securing the negative cable to the vehicle. Follow the cable path and ensure all mounting points are freed.
9
Remove complete negative cable assembly
Once all ground connections and clips are removed, carefully remove the entire negative battery cable assembly from the vehicle. This cable connects both batteries together and provides multiple ground points.
10
Clean battery tray and connection points
Using a wire brush and baking soda solution, thoroughly clean the battery tray, battery posts, and all cable connection points on the starter and ground locations. Remove all corrosion and oxidation. Rinse with water and dry completely.
11
Install new positive battery cable
Route the new positive battery cable assembly following the same path as the original. Secure the cable to the starter solenoid post first, ensuring any other wiring terminals are stacked in the original order. Install the nut and tighten firmly with a 13mm socket. Then connect the cable to the battery posts loosely - do not fully tighten yet.
12
Install new negative battery cable
Route the new negative battery cable assembly following the same path as the original. Connect and tighten the ground terminals to the engine block and chassis ground points using a 13mm socket. Ensure all ground connections are clean and tight. Then connect the cable to the battery posts loosely - do not fully tighten yet.
13
Reinstall batteries
Place both batteries back into the battery tray in their original orientation. Install the battery hold-down clamps and secure with the 13mm bolts. Tighten the hold-downs firmly but do not over-tighten to avoid cracking the battery case.
14
Secure all cable routing
Install all cable routing clips, ties, and retainers to secure both positive and negative cables. Ensure cables are routed away from hot exhaust components, sharp edges, and moving parts. Cables should have minimal slack but not be pulled tight.
15
Final connection and protection
Apply a small amount of dielectric grease to the battery posts. Tighten all battery terminal connections using a 10mm socket - positive terminals first, then negative terminals. Ensure connections are tight and cannot be twisted by hand. Apply additional dielectric grease or anti-corrosion spray to the outside of the terminals after connection.

Reassembly

Verify all cable connections are tight at batteries, starter, and ground points
Ensure no tools or hardware were left in the engine bay
Double-check that positive and negative cables are connected to the correct battery terminals
Verify cables are properly routed and secured away from moving parts and heat sources

Verification

Turn the ignition key to the ON position (do not start) and verify dash lights illuminate normally
Check for any unusual smells or smoke from battery area
Attempt to start the engine - it should crank vigorously with no hesitation
Verify all electrical accessories function properly (lights, radio, power windows, etc.)
With engine running, inspect all cable connections for signs of overheating or arcing
Reset clock and radio presets as needed