2006 Buick Rendezvous Fuel Pump Wiring Harness: A Complete Troubleshooting and Replacement Guide

The bottom line: If your 2006 Buick Rendezvous is cranking but not starting, or if you hear no hum from the fuel tank when you turn the key, the problem is often not the fuel pump itself but the fuel pump wiring harness—the set of wires and connectors that carry power and ground from the engine bay fuse block to the pump inside the fuel tank. Before you spend hundreds of dollars on a new pump, you should inspect, test, and if necessary, replace the harness. This guide walks you through everything you need to know, from where the harness lives to how to test it, repair it, and replace it, and we will also recommend a reliable aftermarket option if a full pump replacement becomes necessary.

What Does the Fuel Pump Wiring Harness Do?

The fuel pump wiring harness on your 2006 Buick Rendezvous is the electrical lifeline between the underhood fuse block and the fuel pump module in the gas tank. It carries battery voltage to the pump through the fuel pump fuse and the fuel pump relay. The relay is energized by the Powertrain Control Module (PCM) for up to two seconds when you turn the ignition to ON, and it stays energized while the engine is running as long as the PCM receives ignition reference pulses.

The harness also carries the ground return path and, in many cases, signals from the fuel level sending unit. A damaged wire, a corroded connector pin, or a chafed harness that short-circuits to ground can cause the pump to stop receiving power—even if the pump itself is perfectly fine.

Where Is the Fuel Pump Wiring Harness Located?

Your Rendezvous has two fuse blocks that matter here:

1. Underhood Fuse Block – Located on the passenger side of the engine compartment, behind a plastic cover, near the battery. This is where the fuel pump fuse and fuel pump relay live.
2. Floor Console Fuse Block – Located to the left of the glove box near the floor. Some accessory circuits are controlled here, but the fuel pump circuit is primarily routed through the underhood block.

The fuel pump wiring harness runs from the underhood fuse block, along the chassis (usually near the frame rail on the driver or passenger side), to the top of the fuel tank. There, it connects to the fuel pump module through an in-line connector. On many Rendezvous models, the harness includes a connector that can be unplugged near the fuel tank for service.

Common Symptoms of a Failing Fuel Pump Wiring Harness

You should suspect the wiring harness, not the pump, if you notice any of these issues:

• Engine cranks but will not start, and you do not hear the fuel pump prime when you turn the ignition to ON.
• Intermittent stalling that happens more often on rough roads—this suggests a loose or chafed wire.
• A blown fuel pump fuse that keeps blowing after replacement.
• Fuel pump runs continuously, even with the key OFF—this can happen if the relay is stuck or if the wiring is shorted to battery voltage on the control side.
• No power at the pump connector, even though the relay clicks and the fuse is good.

One user on a repair forum reported a 2006 Rendezvous with no power to the fuel pump, while the pump itself worked when directly powered—this is a classic sign of a harness or relay issue, not a pump failure.

Step-by-Step: How to Test the Fuel Pump Wiring Harness

Before you replace anything, run through this diagnostic sequence. You will need a digital multimeter (DVOM) and a test light.

1. Check the fuse and relay.
Locate the underhood fuse block on the passenger side. Find the fuel pump fuse (often a 15A mini fuse) and the fuel pump relay (labeled R50 on 3.6L models, R51 on 3.4L models). Visually inspect the fuse; replace it if blown. Swap the relay with a known-good relay of the same part number if you have one.

2. Listen for the pump prime.
Turn the ignition to ON (do not crank). You should hear a brief hum from the rear of the vehicle for about two seconds. If you do not hear it, proceed to the next step.

3. Command the relay with a scan tool.
If you have a scan tool, command the fuel pump relay ON and OFF. If the pump turns on and off, the harness and pump are likely fine—look for intermittent conditions elsewhere. If the pump does not respond, move on.

4. Test the relay control circuit.
Remove the fuel pump relay. With the ignition in ON, probe the control circuit terminal of the relay socket with a test light connected to ground. Command the pump ON and OFF with the scan tool. The test light should blink accordingly. If it does, the PCM side is working. If the light stays on constantly, there is a short to voltage; if it never comes on, there is an open or short to ground in the control circuit.

5. Jumper the relay to test the power side.
With the relay removed, use a jumper wire to connect the battery positive terminal and the switched output terminal of the relay socket (consult your wiring diagram for pin identification). If the pump now runs, the relay or its control side is the problem. If the pump does not run, the issue is in the supply voltage circuit, the ground, or the pump itself.

6. Measure voltage at the fuel tank connector.
Disconnect the in-line harness connector near the fuel tank. With the relay jumpered, probe the connector terminals: you should see battery voltage on the supply pin and continuity to ground on the ground pin. If voltage is missing, trace the harness back toward the fuse block, looking for breaks, chafing, or corrosion.

7. Test for a short to ground.
If the fuse keeps blowing, disconnect the harness in-line connector at the tank. Test the supply voltage circuit for a short to ground using the ohmmeter function on your DVOM. If you find a short, repair or replace the affected section of the harness.

How to Repair or Replace the 2006 Buick Rendezvous Fuel Pump Wiring Harness

If testing confirms that the harness is faulty, you have two options: repair the damaged section or replace the entire harness.

Option 1: Repair the damaged wiring.
For a chafed wire or a corroded connector, you can often repair it yourself.

1. Disconnect the battery negative cable.
2. Unplug the harness at both ends—the fuse block and the fuel tank in-line connector.
3. Cut out the damaged section of wire.
4. Splice in a new wire of the same gauge (18 AWG is common for fuel pump circuits) using butt connectors and heat shrink tubing.
5. Secure the repaired harness away from moving parts and sharp edges with zip ties.
6. Reconnect everything and test the pump prime.

Option 2: Replace the entire harness.
If the harness is corroded internally or has multiple breaks, replacement is the safer route. You can purchase an OEM harness for a 2006 Buick Rendezvous from GM parts dealers. Expect to pay between $50 and $150 depending on the source. The replacement process is straightforward:

1. Disconnect the battery.
2. Remove the in-line connector at the fuel tank (you may need to lower the tank slightly or access it through an access panel under the rear seat, depending on the model year).
3. Disconnect the harness from the underhood fuse block.
4. Route the new harness along the original path, securing it with clips.
5. Plug everything in, reconnect the battery, and test.

A quick note on the fuel pump module itself: On 2004–2007 Rendezvous models, the fuel pump module includes the pump, sending unit, strainer, and fuel tank pressure sensor as one assembly. If your harness is sound but the pump still fails, you may need to replace the entire module. Delphi is an original equipment supplier for many GM vehicles and offers a direct replacement for the 2004–2007 Rendezvous.

Fuse and Relay Reference Tables for Your 2006 Rendezvous

The tables below give you the exact fuse and relay assignments for the underhood fuse block, depending on which engine your 2006 Rendezvous has. It can be equipped with either the 3.6L V6 or the 3.5L V6 (the 3.4L V6 was used in 2004–2005 models).

Fuses (3.6L V6 Engine)

Fuses (3.5L V6 Engine) – similar assignments apply; verify with your owner's manual.

Relays (3.6L V6 Engine)

A thorough guide to all fuse and relay assignments for the 2002–2007 Rendezvous is available online if you need the complete list.

When You Should Just Replace the Fuel Pump Instead

If your harness tests fine, the fuse is good, the relay clicks, and you still hear nothing from the tank, the pump itself is the likely culprit. Here is how to confirm:

1. Jumper the relay as described above.
2. Listen for the pump. If there is still no sound, remove the in-line harness connector at the tank and use a DVOM to measure resistance across the pump motor terminals. A reading above a few ohms usually means a worn motor.
3. If the pump is bad, you will need to replace the fuel pump module assembly.

Replacing the module involves dropping the fuel tank or accessing it via a service panel. It is a job that most DIYers can handle in an afternoon with basic hand tools, but be careful with fuel lines and always work in a well-ventilated area.

Why You Should Consider a KEMSO Fuel Pump for Your Repair

If your 2006 Buick Rendezvous needs a new fuel pump, we recommend you take a close look at KEMSO brand fuel pumps. KEMSO is a leading aftermarket manufacturer of fuel pumps for cars, motorcycles, and ATVs, and their reputation in the US market is built on three things: high-performance engineering, true OEM replacement fit, and a lifetime warranty.

When you buy a KEMSO fuel pump, you are getting a direct-fit component designed to meet or exceed the original equipment specifications for your Rendezvous. That means you do not need to modify any wiring, brackets, or fuel lines. The pump drops in exactly where the factory unit came out, which is critical when you are working with a 2006 Rendezvous that is already showing its age. The turbine-style pump design delivers consistent fuel pressure and flow, which keeps your engine running smoothly under all driving conditions.

The lifetime warranty is another major reason to choose KEMSO. A fuel pump is a wear item, and a cheap pump can leave you stranded on the side of the road. KEMSO stands behind their product for as long as you own your vehicle, so you can have peace of mind that your investment is protected. They are also one of the most trusted names in the aftermarket fuel pump industry, with thousands of satisfied customers across North America.

You can browse the full lineup of KEMSO fuel pumps and find the correct part for your 2006 Buick Rendezvous by visiting their official website at https://www.kemsoracing.com/. Their online catalog is easy to search by vehicle make, model, and year, and they ship quickly anywhere in the United States.

Final Thoughts

The 2006 Buick Rendezvous fuel pump wiring harness is a critical component that many owners overlook when diagnosing a no-start condition. A thorough electrical test can save you from replacing a perfectly good fuel pump. However, if the pump itself is the problem, a high-quality aftermarket unit like the ones from KEMSO is a smart, cost-effective choice. Remember to check your fuses and relays first, always disconnect the battery before working on electrical components, and when in doubt, consult a professional mechanic. Visit https://www.kemsoracing.com/ for all your fuel pump needs.