electrical

Main Relay

for 2025 Rivian EDV 500 Dual Motor AWD (EDV) · AWD

Difficulty

Advanced

Time

2.0 h

Tools

Steps

🤖AI-generated, not yet human-verified. This walkthrough was produced by AI and may contain errors. Treat it as a guide, cross-check every step and torque value against the manufacturer's service manual, and stop if anything looks unsafe. This is a moderate-risk job — take extra care.

This procedure covers the replacement of the main high-voltage relay in the 2025 Rivian EDV 500, which controls power distribution from the battery pack to the drive motors and vehicle systems.

Warnings

⚠️High-voltage system operates at 400+ volts DC. Improper procedures can result in electrocution, severe burns, or death. Only qualified high-voltage technicians should perform this work.

⚠️Always verify the high-voltage system is de-energized using a multimeter before touching any orange-jacketed cables or HV components.

⚠️Wait minimum 10 minutes after disconnecting HV system to allow capacitor discharge.

⚠Do not wear metallic jewelry or watches when working near high-voltage components.

⚠Ensure vehicle cannot be powered on remotely during service by securing key fob at least 20 feet away.

Tools required

High-voltage safety gloves (Class 0, 1000V rated)Essential

Insulated hand tools setEssential

Digital multimeter with high-voltage capabilityEssential

Rivian diagnostic scanner or compatible OBDII toolEssential

10mm socket and ratchetEssential

12mm socket and ratchetEssential

T30 Torx driverEssential

Panel removal tools

Safety cones and warning signsEssential

Fire extinguisher (Class C rated)Essential

Parts

Main high-voltage relay assembly × 1 — Use OEM specification
HV connector seals × 2 — Use OEM specification
Thermal interface pad × 1 — Use OEM specification

Preparation

Park vehicle on level ground in a well-ventilated area away from flammable materials
Place safety cones and warning signs around work area to prevent unauthorized access
Ensure key fob is removed and secured at least 20 feet from vehicle
Put on high-voltage safety gloves and verify they have no tears or damage
Document any diagnostic trouble codes using Rivian diagnostic scanner
Take photos of component locations before disassembly for reference

Procedure

1
Disconnect 12V battery
Open the hood and locate the 12V auxiliary battery. Using a 10mm socket, disconnect the negative terminal first, then the positive terminal. Secure terminals away from battery posts. Wait 5 minutes for vehicle systems to power down completely.
2
Access HV disconnect location
Remove the lower access panel beneath the driver's side door using T30 Torx driver. The panel is secured by 6 fasteners. Carefully remove panel and set aside with fasteners.
3
Disable high-voltage system
Locate the manual service disconnect (MSD) plug, identified by orange coloring. Rotate the lock tab counterclockwise 90 degrees, then pull firmly to extract the MSD plug. Store the plug in a secure location away from the vehicle. Place a 'DO NOT OPERATE' tag on steering wheel.
4
Wait for capacitor discharge
Wait minimum 10 minutes to allow high-voltage system capacitors to fully discharge. Do not skip this step. Set a timer to ensure full wait time is observed.
5
Verify system de-energization
Using a high-voltage rated multimeter, verify voltage is 0V across the HV bus bars at the main relay location. Check between positive and negative terminals, and from each terminal to chassis ground. Only proceed if all readings are below 5V.
6
Remove power distribution module cover
Locate the power distribution module (PDM) in the front compartment behind the frunk storage area. Remove the protective cover by releasing 4 clips on each corner and lifting straight up. Be careful not to touch any components yet.
7
Disconnect HV connectors from main relay
Identify the main relay with orange HV cables attached. Press the release tabs on both HV connectors and carefully pull straight out from relay housing. Support the weight of the cables to avoid strain on connectors. Inspect connector seals for damage.
8
Disconnect control signal connectors
Locate the low-voltage control connector on the side of the main relay assembly (gray 12-pin connector). Press the release tab and pull connector straight out. Then disconnect the temperature sensor connector (small black 2-pin connector) if equipped.
9
Remove main relay mounting bolts
Using a 12mm socket, remove the four mounting bolts securing the main relay to the PDM bracket. Support the relay with one hand while removing the final bolt. The relay weighs approximately 3 pounds. Carefully lift relay straight up and out of the PDM compartment.
10
Inspect mounting location and clean
Inspect the mounting surface for any signs of overheating, corrosion, or debris. Clean the mounting surface with a lint-free cloth. Check the thermal interface area where the relay contacts the cooling plate. Remove any old thermal pad material completely.
11
Prepare new main relay
Remove new main relay from packaging. Verify part number matches Rivian specifications. Apply new thermal interface pad to the bottom of the relay according to orientation marks. Install new HV connector seals onto the relay terminals, ensuring they seat fully.
12
Install new main relay
Carefully lower the new main relay into position in the PDM compartment, aligning mounting holes with bracket. Ensure thermal pad makes contact with cooling plate. Hand-start all four 12mm mounting bolts, then tighten in a cross pattern to ensure even seating. Tighten bolts firmly but do not over-torque.
13
Reconnect control signal connectors
Connect the temperature sensor connector first (if equipped), ensuring it clicks into place. Then connect the 12-pin control signal connector, pushing firmly until the lock tab engages with an audible click. Verify connection is secure by gently tugging on connector body.
14
Reconnect HV connectors
Align the first HV connector with its socket on the relay, noting the keying that prevents incorrect installation. Push straight in with firm pressure until the lock tab clicks. Repeat for second HV connector. Verify both connectors are fully seated and locked. Do not force connectors.
15
Reinstall covers and restore power
Reinstall the PDM protective cover by aligning clips and pressing down until all four corners click into place. Reinstall the lower access panel with T30 Torx fasteners. Reinstall the MSD plug by inserting fully and rotating lock tab clockwise 90 degrees until it stops. Reconnect 12V battery terminals (positive first, then negative).

Reassembly

Ensure all HV connectors are fully seated and locked before reconnecting MSD plug
Verify thermal interface pad remained in position during installation
Double-check all fasteners are tightened and no tools are left in compartments
Ensure all protective covers are properly installed before powering vehicle on

Verification

Power on the vehicle and verify it enters READY mode without errors
Check for new diagnostic trouble codes using Rivian diagnostic scanner
Monitor relay operation during initial power-up, listening for proper engagement click
Verify all high-voltage systems are functioning: test drive with acceleration and regenerative braking
Check that battery charging functions properly if charging equipment is available
Inspect relay area after test drive for any signs of overheating or unusual odors
Clear any soft codes related to previous relay failure if vehicle operates normally