Nissan Micra Boot Release Fix

It's a common frustration for many Nissan Micra owners: the boot simply refuses to open. You press the button, you jiggle the key, but nothing happens. This can be incredibly inconvenient, especially when you need to access your boot quickly. Fortunately, this is often a solvable problem, and with a bit of DIY know-how, you can get your Micra's boot latch working as it should. This guide will walk you through the process of diagnosing and fixing the notorious boot release switch, a frequent culprit behind this issue.

Understanding the Micra Boot Release System

The Nissan Micra, particularly models from a certain era (often cited around the 2003-2010 mark, though variations exist), is known to suffer from a faulty microswitch within the boot release mechanism. This switch, often described as a 'French' component by disgruntled owners, is susceptible to wear and tear, water ingress, and general failure. When this microswitch fails, it interrupts the electrical signal required to activate the boot release solenoid, leaving you locked out.

Common Symptoms of a Faulty Boot Release

Before diving into the repair, it's helpful to recognise the signs:

• The boot release button on the tailgate does not elicit any response.
• The boot may not open even when unlocked with the central locking system.
• You might hear a faint click from the rear of the car when trying to open it, but the latch itself doesn't disengage.
• In some cases, the problem might be intermittent before failing completely.

DIY Repair: A Step-by-Step Guide

The following instructions are based on a common method for bypassing and replacing the faulty microswitch. Remember to work safely and disconnect the battery if you are unsure about any electrical components.

Step 1: Accessing the Boot Latch Mechanism

If your boot is currently stuck closed, you'll need to gain access from the inside.

• Fold down the rear seats.
• Remove the parcel shelf.
• Carefully pull off the plastic cover surrounding the boot door lock mechanism. Start at the arched section in the middle and gently pull it away. You might need to apply a bit of force, but be mindful not to break any clips.

Once the cover is off, you should see where the wiring harness enters the boot door. Trace this wire to a white connector. You'll need to unclip this connector. Look for a sprung clip on one side; depress this and pull the connector apart.

Step 2: Emergency Boot Opening

To open the boot in an emergency, you can temporarily bridge the connection within the white connector.

• Take a small, spade-tipped screwdriver.
• Insert it into the female part of the connector, ensuring it makes contact between the two pins inside. Don't worry, you won't get an electric shock as this is a low-voltage circuit.
• You should hear the door release mechanism activate.

With the boot now open, fully open the lid and identify the two nuts securing the opening latch on the inside of the boot lid. Using a 10mm socket, undo these nuts to release the latch assembly. You'll notice a rubber grommet sealing the wire; push this through and feed the wire out.

Step 3: Disassembling the Latch Housing

Now that the latch is free from the car, you can begin to disassemble it.

• Locate the four star-shaped screws holding the black housing for the latch. Use an appropriate star bit (the exact size may vary) to unscrew these.
• Pull out the black housing. You will likely find a significant amount of a sticky, black substance resembling Blu-Tack. This is generally considered redundant and can be discarded.

Step 4: Identifying and Cutting the Wires

Inside the housing, you'll find a main block with chamfered edges. Two wires will lead into this block.

• Carefully cut these two wires as close to the block as possible. Don't be afraid to cut them – you'll need the cut ends with the connector.
• The main block should separate into two pieces. You may need to release some indented catches. Gentle but firm pressure is usually required here; try not to damage the casing.

Step 5: Removing the Faulty Microswitch

Once the casing is apart, you'll see the problematic microswitch, often described as 'rubbish' or 'French'.

• Hollow out all the components from one side of the casing, leaving just the outer shell. You won't need any of the internal wires or connections from this part of the casing.

Step 6: Installing a Replacement Switch

You'll need to purchase a replacement push-to-make switch. A common recommendation is to get one from Maplin (or a similar electronics retailer), with a product code like JB00A, costing around £0.89.

• Once you have your new switch, carefully cut a square hole in the casing you've prepared. This hole should be just large enough for the connector end of the new switch to pass through.
• The switch should then fit snugly into the casing, with the button end protruding from the open end of the housing, in a similar position to the original microswitch.
• Secure the new switch in place using a strong adhesive, such as superglue.

Step 7: Wiring the New Switch

Now it's time to connect the wires to your new switch.

• Gently strip about 5mm of insulation from each of the wires you cut in Step 4.
• Twist the ends of the wires and pass them through the eyelets on the connectors of your new switch.
• Solder the wires securely in place. It typically makes no difference which wire connects to which terminal on the new switch.

You can now test the new switch by reconnecting the two white connectors and pressing the button. You should notice a much more responsive feel compared to the original switch. Be cautious not to press it excessively in rapid succession, as this could potentially trigger an overheat protection system on the release mechanism.

Step 8: Weatherproofing the Repair

It's crucial to protect the new switch and wiring from water ingress, which was likely a cause of the original failure.

• Fill the casing, with the switch now installed, with silicone sealant. Any inexpensive silicone sealant will suffice.
• Generously apply silicone over and around the button end of the switch. This will not damage the switch.
• Immediately rejoin the two halves of the casing together after applying the silicone.

Step 9: Final Sealing and Reassembly

Further sealing is essential for longevity.

• Apply silicone sealant around the entire exterior of the casing and particularly where you made your solder connections (where the old Blu-Tack was).
• You may find a large cavity remaining where the wires protrude; fill this with more silicone.
• Carefully place the main casing back into the latch housing and secure it with the star screws.
• Crucially, allow the silicone at least 24 hours to dry completely. Resist the temptation to test the switch before it's fully cured.

Once the silicone has dried, reassemble all the components back into the boot lid, reconnect the wiring harness, and refit the plastic covers. Your boot release should now function correctly.

Alternative Solution: Dashboard Switch

For those who prefer an internal operating switch, an alternative is to extend the wires from the boot latch to the dashboard.

• Connect two lengths of wire (standard 5-amp wire is suitable) to the cut ends of the wires from Step 4.
• Route these wires back to the dashboard of your car.
• Mount a suitable switch on the dashboard, allowing you to open the boot directly from the driver's seat.

You could even combine both solutions for maximum convenience!

Troubleshooting and FAQs

Q1: My boot is still not opening after the repair. What could be wrong?

A: Double-check all your wiring connections, ensuring they are secure and soldered correctly. Verify that the new switch is functioning independently. If the problem persists, the issue might lie with the boot release solenoid itself or the wiring loom leading to it.

Q2: What kind of silicone sealant should I use?

A: Any general-purpose silicone sealant will work. The primary goal is to create a waterproof barrier around the new switch and connections. Clear or black silicone is usually preferred for aesthetics.

Q3: Can I use a different type of switch?

A: While a push-to-make switch is ideal due to its momentary action, you could potentially use other types if they fit and provide the correct electrical function. However, the push-to-make switch is the most straightforward replacement for the original microswitch.

Q4: Is it safe to bridge the connector in Step 2?

A: Yes, it is generally safe to briefly bridge the connector with a screwdriver as described. The circuit operates at a low voltage and is designed to be activated by the switch. However, always exercise caution when working with electrical components and avoid prolonged bridging, which could potentially cause overheating.

Q5: How do I know if the microswitch itself has failed?

A: If you have continuity testing capabilities with a multimeter, you can test the original microswitch. When pressed, it should show a closed circuit (low resistance). If it remains open circuit (high resistance) or shows erratic readings, the switch has likely failed.

Fixing a stubborn Micra boot release can seem daunting, but by following these steps, you can successfully restore this essential function. Remember to work patiently and methodically, and enjoy the satisfaction of a job well done!