How to Fix Your Maxima's Flickering HID Lights with a Relay Harness

How to Fix Relay Issue

A common electrical gremlin for 2020 Nissan Maxima owners involves issues with relays, particularly when installing aftermarket lighting like HID or LED kits. These problems often manifest as flickering lights, buzzing noises, or a complete failure to operate, and the root cause frequently traces back to improper installation without the necessary supporting hardware. As one owner shared about their aftermarket HID fog lights: "The kit worked for about a good 2 weeks but then I started having problems with the passenger side fog. It goes in & out." This intermittent failure is a classic sign of a relay-related electrical issue.

Symptoms

The most frequently reported symptom is an intermittent failure of aftermarket lighting, such as HID fog lights or LED conversions. Owners describe a scenario where the new lights work perfectly for a short period, then begin to flicker, go out entirely, or only work on one side. This "in & out" behavior is a direct indicator of an unstable electrical connection or an overloaded circuit that a standard factory wiring setup isn't designed to handle.

Another clear symptom is the presence of unusual electrical noises. A persistent buzzing noise from the engine bay or the general area of the installed lights often accompanies these failures. This buzz is typically the sound of a relay struggling to engage or disengage properly, or it can be the ballast for an HID kit straining due to insufficient voltage. It’s an audible warning that the electrical system is under stress.

In more severe cases, the symptoms can escalate beyond accessory lights. Owners have reported issues with starting, where turning the ignition key results in nothing—no dash lights, no crank, just a click or complete silence. While this can be related to the main starter relay or ignition switch, the principle is similar: a relay has failed to bridge the connection needed to deliver high current. One owner troubleshooting a no-start condition noted they found "no spark no fuel just air" after checking fuses and relays, pointing to a critical failure in the power distribution system.

Finally, the symptom of pulling is often described in the context of electrical draw. When a circuit is shorted or a component like a faulty relay or HID ballast fails, it can create a parasitic drain. This slowly pulls voltage from the battery, potentially leading to a dead battery overnight. The cumulative effect of these electrical issues—flickering lights, buzzing, failed starts—creates a significant headache for owners trying to diagnose the root cause.

Most Likely Cause

Based on owner reports, the primary cause of relay issues in this context is the installation of aftermarket high-draw electrical components—specifically HID (High-Intensity Discharge) or high-power LED lighting kits—without a proper relay harness. The factory wiring and switches in your Maxima are designed for the specific current draw of standard halogen bulbs. HID kits, which include a ballast and require a high-voltage pulse to ignite, place a much larger demand on the circuit.

When you plug an HID kit directly into the factory fog light socket, you are forcing that original wiring to carry a load it wasn't engineered for. This causes excessive heat, voltage drop, and instability. As one owner wisely asked before installation: "do i need a relay harness with my hid kit?? i want to install a hid kit on my foglights, but wondering if it would damage my wires when without a relay harness." The answer is a definitive yes. Operating without a harness can damage the factory wires and the vehicle's body control module over time, leading to the intermittent operation and failures owners experience. The relay in a dedicated harness acts as a robust switch, using a small signal from the factory wiring to trigger a new, high-current circuit directly from the battery, protecting your vehicle's delicate electronics.

How to Diagnose

Diagnosing a relay issue requires a methodical approach, starting with the most recent modifications. If you are experiencing problems with aftermarket lights, your first step is to visually and audibly inspect the installation. Turn on the problematic lights and listen closely near the light housing and in the engine bay fuse box area for a buzzing noise. Observe if the lights flicker or fail to strike. Immediately revert to the original halogen bulbs if possible. If the problem disappears with the stock bulbs, you have confirmed the issue is with the aftermarket kit or its installation.

Next, you need to check the integrity of the installation itself. Inspect all connections for the aftermarket kit. Are the ground connections clean, tight, and attached to bare metal? Are all wire taps or connectors secure? A common fault point is a poor ground, which will cause all manner of erratic behavior. Follow the wiring from the battery to the relay to the ballasts and lights, looking for any pinched, frayed, or melted wires.

For no-start conditions or issues beyond lighting, you must locate and test the specific relay. Consult your owner's manual to locate the fuse and relay boxes (typically under the hood and inside the cabin). Find the relay associated with your problem circuit (e.g., starter relay, fuel pump relay). The simplest test is substitution: swap the suspect relay with an identical, known-good one from another non-critical circuit (like the horn or A/C relay). If the problem moves to the other circuit, you've found a bad relay. A more advanced test involves using a multimeter to check for battery voltage at the relay socket pins when the ignition is in the "ON" position, verifying the control signal from the switch is arriving.

If the problem is elusive, consider the possibility of a short circuit introduced during installation. As one owner discovered, "I found a wrench that was laying in my engine bay right by the starter, I have no idea what is was doing there..." Foreign metal objects can bridge connections and cause shorts. Do a thorough visual inspection of the engine bay, especially in areas where you or a shop recently worked, to ensure no tools or debris are creating an accidental path to ground.

Step-by-Step Fix

The fix centers on properly installing a relay harness for any aftermarket HID or high-power LED kit. Here is the detailed process:

1. Gather Parts and Disconnect Battery: First, purchase a high-quality HID relay harness specific to your vehicle's make and model. This harness will include a relay, an in-line fuse, and all necessary connectors. Before any work, always disconnect the negative terminal of your car's battery to prevent shorts or electrical shocks.

2. Remove the Faulty/Incorrect Installation: Carefully uninstall the aftermarket HID kit that was plugged directly into the factory harness. Disconnect the ballasts and remove the bulbs from the fog light housings. Take this time to inspect the factory plug for any signs of melting or heat damage.

3. Mount the Relay: Choose a secure, clean location in the engine bay to mount the new relay. It should be away from extreme heat sources like the exhaust manifold. Use the provided bracket and a bolt or, as one resourceful owner did, "I went to Lowes and got some industrial strength Velcro and some zip ties." A secure mounting prevents the relay from bouncing and causing intermittent connections.

4. Connect the Power Wires: Run the harness's heavy-gauge red power wire to the positive battery terminal. Install the provided fuse (usually 15-20 amps) into the fuse holder before making the final connection. This fuse is critical for protecting your entire car's electrical system from a short in your new harness.

5. Establish a Solid Ground: Connect the harness's black ground wire to a clean, unpainted metal point on the vehicle's chassis or body. Scrape away any paint or rust to ensure metal-to-metal contact. A poor ground is the number one cause of relay harness failure.

6. Connect the Trigger Wires: This is the key step. The harness will have two thin wires (often blue and white). These connect to the positive and negative wires of the vehicle's original fog light plug. You will typically use posi-tap connectors or similar to tap into these signals. This low-current connection is what tells your new relay to turn on, without placing load on the factory switch.

7. Connect the Output to Ballasts: Finally, plug the harness's output connectors into your HID ballasts. Ensure all connections are snug and weatherproof if necessary. Reinstall the HID bulbs into the fog light housings.

8. Reconnect Battery and Test: Reconnect the negative battery terminal. Turn on your vehicle's ignition and activate the fog lights. You should hear a confident "click" from the relay and the HID lights should strike immediately and consistently, without flicker or buzz. As one owner who fixed their issue can attest, the proper harness resolves the "in & out" problem for good.

Parts and Tools Needed

• HID/LED Relay Harness: This is not a generic part. You need one compatible with the 2020 Maxima and your specific kit (often labeled for "9005/HB3" or "H11" fog lights). A quality harness includes integrated fusing.
• Basic Hand Tools: Set of screwdrivers (Phillips and flathead), socket set, and wrenches.
• Wire Management Supplies: Zip ties and electrical tape or wire loom to secure the new wiring neatly away from moving parts and heat.
• Connectors (if not included): Posi-tap connectors or solder and heat shrink tubing for making secure, sealed connections to the trigger wires.
• Multimeter: Essential for diagnosing no-start conditions by checking for power and ground at relay sockets.
• Cleaning Supplies: Wire brush or sandpaper to clean grounding points to bare metal.

Real Owner Costs

The cost to fix a relay issue varies dramatically based on whether you DIY or hire a shop, and the root of the problem.

For a DIY fix on an aftermarket lighting issue, the cost is relatively low. The primary expense is the relay harness itself. As one owner noted, "I brought a pair of HID Fog Light Kit on eBay for about $85." A quality relay harness to support that kit would typically cost an additional $25 to $40. With basic tools already on hand, the total DIY cost is between $25 and $125, depending on if you need to purchase the lighting kit as well.

If you choose to have a professional install a relay harness or diagnose a complex electrical fault, labor costs become the major factor. One owner referenced a shop quote, stating, "I won't have to pay another $150 for a shop to put it on." This $150 likely represents 1-2 hours of labor at a typical shop rate. For a more complex no-start diagnosis involving relay testing and electrical tracing, labor time can increase significantly. While not a direct quote for the Maxima, an owner mentioned the scale of professional tools, noting a "Mac tools $6k scanner," hinting at the high diagnostic capability and associated cost of professional shops. A full diagnosis and repair for an intermittent starting relay issue at a shop could easily range from $200 to $500, factoring in parts and 2-3 hours of labor.

Prevention

The best prevention is to always use a dedicated relay harness when installing any aftermarket component that draws more power than the stock part it replaces. This includes HID headlight or fog light kits, high-output LED light bars, powerful audio amplifiers, or aftermarket cooling fans. Never assume the factory wiring can handle the extra load.

When installing any wiring, take your time. Secure all wires with zip ties away from sharp edges, hot surfaces (like the radiator fans or exhaust), and moving parts. Use proper connectors—avoid simple twist-and-tape methods. Ensure every ground connection is to clean, bare metal. Periodically inspect aftermarket installations, especially before long trips, to ensure nothing has come loose or worn through. Investing in quality components from reputable brands from the start will also prevent the headaches of premature failure.

What Owners Say

Real experiences from NISSAN owners:

Success Stories

"So I brought a pair of HID Fog Light Kit on eBay for about $85. The kit worked for about a good 2 weeks but then I started having problems with the passenger side fog." — BlackMaximus04 ($85) (source)

"The kit worked for about a good 2 weeks but then I started having problems with the passenger side fog. It goes in & out." — BlackMaximus04 (source)

Owner Experiences

"If you could look in your FSM that would be great! I found a wrench that was laying in my engine bay right by the starter, I have no idea what is was doing there..." — RoroandRobin (source)

"Quote: Originally Posted by 95CustomMaxima Wiggling the key does nothing... I've called everywhere and no one can get the switch until at least Tuesday.." — RoroandRobin (source)

"Quote: Originally Posted by noahwise63 My scanner isn’t picking up any codes nor is it communicating to the dlc. All fuses good and relays but no spark no fuel just air." — wxm (source)

Real Repair Costs

"I went to Lowes and got some industrial strength Velcro and some zip ties. Now I'm excited to get it on there & the fact I won't have to pay another $150 for a shop to put it on." — Grego214 (source)

"I am at a lose of what is causing this to happen, I would just say screw the car but I can't afford another car it's all I got. I have even hooked up a Mac tools $6k scanner up to it and couldn't figure any out I could turn on each cylinder and it would obviously run better .. so if anyone has any ideas please let me know.. good troubleshooting and parts cannon for sure." — Child_uv_KoRn (source)

"I have even hooked up a Mac tools $6k scanner up to it and couldn't figure any out I could turn on each cylinder and it would obviously run better .. so if anyone has any ideas please let me know.. good troubleshooting and parts cannon for sure." — Child_uv_KoRn (source)

FAQ

Q: Do I absolutely need a relay harness for HID fog lights on my Maxima? A: Yes, unequivocally. The factory wiring and switch are not designed for the initial high-voltage surge and operating load of HID ballasts. Running HIDs without a relay harness will lead to flickering, premature failure of the bulbs or ballasts, damage to the factory wiring due to heat, and can potentially blow fuses or damage the body control module. As confirmed by owner experiences, operation without one leads to problems within weeks.

Q: How long does it take to install a relay harness? A: For a competent DIYer, the installation of a relay harness for fog lights is a 1-2 hour job. This includes time to disconnect the battery, remove the old incorrect wiring, find suitable mounting points for the relay, run wires neatly, make secure connections, and test the system. Taking your time to do it neatly is crucial for long-term reliability.

Q: Can I drive my Maxima with flickering HID lights or a buzzing relay? A: It is not recommended. A buzzing relay indicates it is struggling and could fail completely, leaving you without fog lights. More importantly, the electrical instability can cause voltage fluctuations that may affect other sensitive electronics in your vehicle. In a worst-case scenario, a failing component could create a short circuit, posing a fire risk. Address the issue promptly.

Q: My car just clicks once and won't start. Could it be a relay? A: Absolutely. A single loud click when turning the key to "START" is the classic symptom of a faulty starter relay or a weak connection at one. The click is the sound of the relay solenoid engaging, but it may not be passing sufficient current to the starter motor. This is a distinct possibility and one of the first components to check after verifying battery health.

Q: Is this a common issue on the 2020 Maxima? A: The 2020 Maxima itself does not have a widespread, inherent factory defect with its relays. However, the issue is extremely common among owners who install aftermarket lighting without the proper supporting hardware. The forums are filled with posts from owners of this generation and others experiencing identical problems after modifying their lighting, making it a frequent "owner-induced" common issue.

Q: Should I attempt this DIY or take it to a mechanic? A: If the problem is isolated to aftermarket fog lights or headlights you installed, and you are comfortable with basic hand tools and following wiring instructions, this is a very achievable DIY project. The cost savings are significant. However, if the problem involves a no-start condition, affects multiple systems, or you are not confident tracing electrical circuits, seeking a professional mechanic is the wiser choice. Electrical diagnostics can be time-consuming and frustrating without experience.