Nissan AD relay (11 body): location, diagnosis and replacement

Nissan AD with body 11th generation (1995–2001) is a legendary sedan known for its reliability and ease of maintenance. However, even such machines eventually develop problems with electrical equipment, and most often the culprits are relay. These small devices control the operation of the headlights, cooling fan, fuel pump and other critical systems. If your AD started to behave strangely - the turn signals do not turn on, the engine stalls or the radiator overheats - the relay may be to blame.

In this article we will look at where are the relays located in Nissan AD (11 body), how to check them with a multimeter, what symptoms indicate a malfunction and how to correctly replace the part without consequences. We will also give a unique table of correspondence between relays and the circuits they control, which you will not find in standard manuals. The material will be useful to both beginners and experienced car owners who are faced with electrical problems.

Where are the relays located in Nissan AD (11 body)? Location and diagrams

B Nissan AD 11th body relays are concentrated in three main blocks:

• 🔧 Main relay and fuse box — located under the hood, to the left of the steering column (driver's side). It is accessible after removing the cover.
• 🚗 Block in the cabin — located behind the glove compartment (removal of the plastic panel is required). The relays for the climate system and audio system are located here.
• ⚡ Additional block — under the center console (next to the gearshift lever). Contains ABS and ignition system relays.

The most important block is engine compartment. It contains relays responsible for:

• 💡 Lighting (low/high beam, dimensions)
• ⛽ Fuel pump
• 🌀 Radiator cooling fan
• 🔋Battery charging (voltage regulator relay)

To get to the block, open the hood and find a black plastic box with a lid. On the inside of the cover there is usually a diagram of the location of the relays and fuses. If there is no diagram, use our table below.

Nissan AD relay table (11 body) with assignment explanation

Below is unique correspondence table of relays and controlled circuits for Nissan AD (11 body), compiled on the basis of factory manuals and repair experience. Please note: location may vary slightly depending on year of manufacture and equipment.

Relay number	Purpose	Symptoms of a problem	Relay type (rating)
R1	Cooling Fan Relay (Low Speed)	Engine overheating, fan does not turn on at low speeds	12V, 30A
R2	Cooling Fan Relay (High Speed)	The fan does not work at high speeds, the overheating lamp lights up	12V, 40A
R3	Fuel pump relay	The engine does not start, there is no pressure in the fuel rail	12V, 20A
R4	Low beam relay (left headlight)	Low beam on one side does not work	12V, 15A
R5	High beam relay	High beams do not turn on or blink randomly	12V, 15A

If your relay does not correspond to the specified rating (for example, instead of 30A it is 20A), this may indicate a previous repair with errors. Never install a lower rated relay - this will lead to contact melting or fire!

⚠️ Attention! Relay R3 (fuel pump) often counterfeited. The original relay is marked 25230-4M000 or 25230-4M005 and costs from 800 rubles. Cheap analogues (200–300 rubles) last 1–2 months.

How to test a relay in a Nissan AD with a multimeter: step-by-step instructions

Checking the relay takes 5–10 minutes and does not require special skills. You will need:

• 🔧 Multimeter (in continuity mode or resistance measurement mode)
• 🔌 Jumper wires (you can use paper clips)
• 📄 Pinout diagram (see below)

Verification algorithm:

1. Remove the relay from the block (carefully pry it off with a screwdriver if it is “stuck”).
2. Look at the relay body - there should be a diagram with contact numbers (usually 85, 86, 87, 30).
3. Connect the multimeter in dialing mode to the contacts 85 And 86 (coil). There must be resistance 50–120 Ohm. If “infinity” is a break, if “0” is a short circuit.
4. Apply 12V to the contacts 85 And 86 (possible from the battery via jumpers). There should be a click - this is the moving contact.
5. Call contacts 30 And 87 (power part). Without applying voltage - “infinity”, after applying - “0 Ohm” (short circuit).

If the relay does not click or ring, it is faulty. Also inspect the contacts for melting or oxidation. Often the problem lies not in the relay itself, but in poor contact in the block.

Remove the relay from the block

Check coil resistance (85–86)

Apply 12V to the coil (there should be a click)

Check the short circuit of the power section (30–87)

Inspect contacts for melting -->

Typical relay malfunctions in Nissan AD and their symptoms

Relay in Nissan AD fail for three main reasons:

1. Natural wear and tear — over time, the moving contacts oxidize or burn.
2. Power surges - a faulty generator or battery can “kill” the relay in a few days.
3. Moisture - if the relay block is not sealed, the contacts will corrode.

A relay malfunction can be recognized by the following signs:

• 🚨 Engine won't start — the fuel pump relay is at fault (R3) or main relay (R6). Check if the sound of the pump is heard when the ignition is turned on.
• 🔥 Engine overheating - cooling fan does not work (relay R1 or R2). Stop and check immediately!
• 💡 The light blinks or does not turn on — problems with the lighting relay (R4, R5). Often accompanied by melting of contacts in the block.
• 🔋 The battery is running low — the voltage regulator relay is faulty (R7). Check the voltage on the battery with the engine running (should be 13.8–14.5V).

Relay malfunction is especially insidious R3 (fuel pump). If it is “stuck” in the closed state, the engine will stall while driving, and restarting will be impossible until the relay is replaced. Always carry a spare fuel pump relay with you — it costs a penny, but it can save you on the road.

⚠️ Attention! If after replacing the fuel pump relay (R3) the engine still does not start, check fuse F15 (15A) in the same block. It often burns out when there is a short circuit in the pump circuit.

Replacing a relay in a Nissan AD: step-by-step algorithm with photos

Replacing a relay is a simple operation, but there are some nuances. Follow the instructions to avoid damaging the unit or contacts:

1. Disconnect the battery (remove the negative terminal). This will prevent short circuit.
2. Remove the relay box cover. It is secured under the hood with two latches, and in the interior with screws.
3. Find the faulty relay according to the table above or the diagram on the block cover.
4. Remove the relay with a gentle rocking motion. If it is “stuck”, do not pull it - use a flat-head screwdriver, prying it from the side.
5. Install a new relay the same markings. Please note polarity - the contacts must match.
6. Check the system operation. For example, if you replaced the fan relay, start the engine and wait for the fan to operate (at a temperature of ~95°C).

If after replacing the relay the problem remains, the reasons may be as follows:

• 🔌 Broken wiring - test the circuit with a multimeter.
• 🛠️ Control sensor malfunction (for example, a temperature sensor for a fan).
• 🔋 Poor contact in the block — clean oxidized connectors.

The photo below shows the process of replacing the cooling fan relay (R1):

Photo of the relay replacement process

The image shows how the relay is carefully removed from the block using a plastic spatula. Pay attention to the condition of the contacts - they must be clean, without green deposits (oxidation).

Which relays are best to buy for Nissan AD? Review of manufacturers

There are three categories of relays on the market:

1. Original (Nissan) - the most reliable, but expensive (from 800 rubles). Marking starts with 25230-.
2. Premium analogues — Hella, Bosch, Valeo. Price 400–600 rubles, quality close to the original.
3. Budget analogues — ERA, Febi, JP Group. They cost 150–300 rubles, but the resource is 2–3 times lower.

Recommendations for selection:

• 🔧 For fuel pump And cooling fan take only the original or Hella - savings here will result in breakdowns on the road.
• 💡 For lighting analogues will do Bosch or Valeo.
• ⚡ For charging relay (R7) the original is required - low-quality analogues can damage the generator.

When purchasing, pay attention to:

• 📌 Rated current (must match the original).
• 📌 Contact type - in Nissan AD Relays with “legs” for a standard connector are used.
• 📌 Packaging — original relays are sold in branded bags with a hologram.

⚠️ Attention! On the Internet they often sell “universal” relays with the inscription 12V 30A/40A no markings. These parts are not suitable for Nissan AD - they cannot withstand the load and burn after 1-2 months.

Common mistakes when replacing relays and how to avoid them

Even experienced car owners make mistakes when working with relays. Here are the most common:

1. Ignoring the fuse. If the relay burns out, check the corresponding fuse - it could have blown for the same reason. For example, for a fan relay (R1/R2) this is a fuse F10 (30A).
2. Installing a relay at random. Some relays look similar, but have different pinouts. For example, low beam relay (R4) and distant (R5) visually identical, but not interchangeable!
3. Using the wrong tool. Do not pull out the relay with pliers - this will bend the contacts. Use a plastic spatula or thin screwdriver.
4. Checking the relay without load. The relay may “click” when 12V is applied, but cannot handle the actual current. Always test it under load (for example, by connecting a light bulb).

Another common mistake is do not clean the block contacts before installing a new relay. Oxidized or burnt connectors will lead to repeated failure. To clean use:

• 🧴 Special contact cleaner (For example, Contact Cleaner).
• 🧼 Isopropyl alcohol (at least 90%).
• 🧽 Fine sandpaper (for strong oxides).

After cleaning, apply to contacts conductive lubricant (For example, Liqui Moly Kontaktreiniger) - this will protect them from corrosion.

FAQ: Frequently asked questions about the relay in Nissan AD (11 body)

Is it possible to replace the relay with a more powerful one (for example, 30A instead of 20A)?

No! The relay is designed for a specific load. If you install a more powerful one, it will not be able to properly protect the circuit from overload. For example, the fuel pump relay (R3) at 20A, when the current is exceeded, it should open, and the 30A relay will pass a dangerous current, which will lead to melting of the wiring.

Why does a new relay burn out quickly?

There are two reasons:

1. Short circuit in the circuit — Check the wiring for open circuit or short to ground.
2. Poor contact in the block — oxidized or burnt connectors create additional resistance, which causes the relay to overheat.

Also make sure that you buy an original relay and not a fake one.

How to test a relay without a multimeter?

Can be used control lamp or continuity test from wire and battery:

1. Connect a lamp (12V) to the contacts 85 And 86 - if the relay is working properly, when 12V is supplied, the lamp will light up.
2. Connect the lamp to 30 And 87 — when the relay is activated, the lamp should light up.

If there is no lamp, use a battery (9V) and a thin wire - when closing the contacts 85–86 there should be a click.

Where to buy original relays for Nissan AD?

Original relays can be ordered:

• 🛒 Official Nissan dealers - guarantee of authenticity, but high price.
• 🌍 Online stores: Exist.ru, Autodoc.ru, Emex.ru (search by article number, for example, 25230-4M000).
• 🏗️ Showdown - cheaper, but there is a risk of running into a worn relay.

Before purchasing, check the relay article number with the table at the beginning of the article!

Is it possible to repair a burnt out relay?

Theoretically yes, but not recommended. A relay is a sealed device, and once opened, its reliability drops sharply. If you still want to try:

1. Carefully open the case (it is usually glued or snapped together).
2. Clean the moving contacts from carbon deposits (use alcohol or an eraser).
3. Check the spring - if it is weakened, the relay will not operate reliably.

This type of repair is a temporary solution. For continuous use, buy a new relay.