Rear Washer Jet & MOT: Fail or Pass?

There's often a lively debate among drivers and even some mechanics regarding what constitutes an MOT failure, and few topics spark as much confusion as the humble rear washer jet. Will a rear washer jet that refuses to supply water lead to a dreaded red 'failure' slip? Or is it merely an inconvenience, something you might address at your leisure? This article aims to settle the argument once and for all, delving into the specifics of the MOT test manual and offering practical advice for when your rear screen goes unwashable.

You're not alone if you've pondered this question. The MOT test is comprehensive, designed to ensure your vehicle meets minimum safety and environmental standards. However, not every component on your car is subject to the same rigorous scrutiny. Understanding the precise requirements, particularly concerning visibility, is key to navigating the test successfully and avoiding unnecessary stress or repairs.

The MOT Manual: What Does It Really Say?

To cut straight to the chase and put an end to the speculation: for a standard passenger car, a non-functioning rear washer jet will not cause an MOT failure. This might surprise some, especially given how critical windscreen washers are for forward visibility.

The official MOT inspection manual, specifically the section relating to 'Wipers and Washers' (often referenced as VTN 4.1.2), states that "Windscreen wipers and washers must operate correctly to give the driver a clear view of the road." The crucial word here is 'windscreen'. The test explicitly focuses on the front windscreen and its associated cleaning systems, as this directly impacts the driver's primary field of vision.

While a rear wiper blade must be present and function correctly if fitted, the *supply of water* to the rear screen is not a testable item for passenger vehicles. This means that even if your rear wiper works perfectly but no fluid squirts out, your vehicle should still pass the MOT test on this point. It's a common misconception that all wipers and washers, front and rear, are equally critical for the test.

Understanding the Nuances: Front vs. Rear Visibility

The distinction between front and rear visibility in the context of the MOT is fundamental. The test's primary concern is ensuring the driver has an unobstructed and clear view ahead. This encompasses the condition of the windscreen itself, the functionality of the front wipers (including their blades), and the ability of the front washer jets to deliver fluid effectively to clean the screen.

Think about driving conditions: rain, dirt, and road grime accumulate on the windscreen, directly impairing your ability to see hazards, other vehicles, and road signs. Without working front wipers and washers, safe driving becomes impossible. This is why a defective front washer system is a definite MOT failure.

For the rear, while clear visibility is certainly desirable for reversing and checking blind spots, it is not deemed as critical for the immediate safety of forward motion. Many older vehicles, or even some modern budget models, don't even come equipped with a rear wiper or washer jet at all. If it's not fitted from the factory, it can't be tested. If it *is* fitted, the wiper itself must work, but the washer's fluid delivery is overlooked by the test.

Why the Confusion Persists

The widespread belief that a non-working rear washer jet will fail an MOT stems from a few factors:

1. Generalisation: People often generalise the rules for the front windscreen to the entire vehicle. If the front needs to work, surely the back does too? Not so, in this specific instance.
2. Safety Perception: A non-functional washer jet is clearly an impairment to visibility, even if it's the rear. Many naturally assume anything impacting visibility would be an MOT concern.
3. Advisories: While not a 'fail', a tester might sometimes issue an advisory note for a non-working rear washer. An advisory simply means something is noted as defective or potentially problematic but doesn't warrant a failure. It's a recommendation for future repair, not a mandatory fix for passing the test. This can sometimes be misinterpreted as a near-fail.
4. Tester Discretion (Rare but Possible): While the manual is clear, occasionally a less experienced or overly cautious tester might misinterpret the rules. However, according to the official guidelines, a rear washer jet alone should not be a fail.

Common Reasons Your Rear Washer Jet Might Fail

Even though it won't fail your MOT, a non-functioning rear washer jet is an annoyance you'll want to address. Here are the most common culprits and how to approach them:

• Empty Fluid Reservoir

  This is the simplest and most common reason. It sounds obvious, but many drivers forget to top up their fluid reservoir regularly. Check the level, and if it's low, fill it with a good quality screen wash solution. Using plain water, especially in colder months, can lead to freezing and potential damage.

• Blocked Nozzle or Pipe

  Just like the front, rear washer jets can become clogged with dirt, wax, or even algae if plain water has been used. The small opening of the nozzle is particularly susceptible. Sometimes, the pipe leading to the nozzle can also get kinked or accumulate debris.

  Solution: Try using a thin needle or a pin to gently clear the nozzle opening. If that doesn't work, you might need to remove the nozzle (they often just pop out) and inspect the pipe. As one driver found, sometimes simply detaching the nozzle and running the pump can dislodge blockages within the pipe, allowing the fluid to flow freely.

• Frozen System

  During winter months, if you haven't used appropriate screen wash with anti-freeze properties, the water in the reservoir, pump, or lines can freeze. This will prevent any fluid from reaching the jet.

  Solution: Park your car in a warm garage or a sunny spot to allow the system to thaw. Once thawed, drain any plain water and refill with a proper screen wash solution designed for cold weather.

• Pump Issues

  Your car has an electric pump (or sometimes two, one for front and one for rear) that pushes the fluid from the reservoir to the jets. If the pump itself is faulty, no fluid will be delivered. You might hear a whirring sound when you activate the wash function, but no fluid, indicating the pump is working but perhaps not drawing fluid. Or you might hear nothing at all.

  

  Solution: Check the pump's electrical connection. If you hear no sound, check the fuse box for a blown fuse related to the washer system. If the fuse is fine and you hear no sound, the pump might need replacing. If you hear it, but no fluid, the pump might be clogged or faulty.

• Electrical Problems

  Less common but possible are electrical issues such as a blown fuse, a faulty relay, or damaged wiring leading to the pump or the washer stalk on your steering column. If both front and rear washers stop working simultaneously, it's more likely to be a shared fuse or pump issue.

  Solution: Consult your car's manual for the fuse box diagram and check the relevant fuse. If the fuse is fine, diagnosing electrical issues can be more complex and might require a professional.

DIY Fixes: Getting Your Rear Washer Flowing Again

Before rushing to a garage, try these simple troubleshooting steps, inspired by common successes:

1. Check the Fluid Level: This is step one. Ensure your fluid reservoir is topped up with good quality screen wash.
2. Inspect and Clear the Nozzle: Locate the rear washer jet. It's usually small and located near the base of the rear wiper arm or high on the tailgate. Use a fine pin or needle to gently poke into the opening, dislodging any debris.
3. Disconnect and Test the Pipe: If clearing the nozzle doesn't work, try to carefully detach the hose from the rear of the nozzle. This often just pulls off or unclips. Once detached, activate the rear washer. If fluid now squirts freely from the hose, the blockage is definitely in the nozzle itself. Clean or replace the nozzle. If no fluid comes out, the blockage is further back in the pipe or the pump system.
4. Bleed the System: Sometimes air can get trapped in the lines. With the nozzle off (if you removed it), try activating the washer for an extended period (10-15 seconds) to see if the fluid eventually pushes through.
5. Thaw the System: If it's cold, park your car in a warm place for a few hours. Once thawed, pump the washer to clear any remaining ice.

Beyond the MOT: Why a Working Rear Washer Matters

While a non-functioning rear washer jet won't fail your MOT, having a clear view out of your rear window is undeniably important for safe driving. Reversing, checking blind spots, and monitoring traffic behind you all rely on good rear visibility. A dirty rear screen can obscure your view, making these manoeuvres riskier. Investing a little time in maintaining this often-overlooked feature is a small effort for a significant safety benefit.

Furthermore, regular maintenance of all your vehicle's systems, even those not strictly covered by the MOT, contributes to the overall longevity and reliability of your car. Neglecting minor issues can sometimes lead to larger, more expensive problems down the line.

Frequently Asked Questions (FAQs)

Q: Will a non-functioning front washer jet fail an MOT?
A: Absolutely, yes. The front windscreen wipers and washers are critical for the driver's clear view of the road and are a mandatory check during the MOT. A failure here will result in a failed test.

Q: My rear wiper works, but it's very slow. Is that an MOT failure?
A: The MOT manual states that wipers must operate correctly. While it doesn't specify speed, if the wiper is so slow that it doesn't effectively clear the screen or appears to be seizing, a tester might deem it a defect. However, the primary focus for rear wipers is that they *do* work if fitted.

Q: Can I get an advisory for a non-working rear washer jet?
A: Yes, it's possible. While it's not a reason for failure, a tester might note it as an advisory to inform you that it's defective and recommend you get it fixed for better visibility and safety.

Q: How often should I check my washer fluid?
A: It's good practice to check your washer fluid level regularly, perhaps once a month or whenever you refuel your car. Top it up with a good quality screen wash, especially before long journeys or during seasonal changes.

Q: What type of fluid should I use in my washer bottle?
A: Always use a dedicated screen wash solution. These are formulated to clean effectively, prevent freezing in winter, and avoid the growth of algae or mould that can clog your system. Avoid using plain tap water, especially in cold weather.

Q: My washer jets are spraying weakly, what could be the issue?
A: Weak spray often indicates a partial blockage in the nozzles or pipes, or a failing pump that isn't generating enough pressure. Start by clearing the nozzles and checking the fluid level.

In conclusion, while the mystery of the rear washer jet and the MOT test can now be put to rest – it won't cause a failure – it's always advisable to ensure all aspects of your vehicle are in optimal working order. A clear view, front and rear, contributes significantly to safer driving for everyone on the road.

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