2012 Mercedes-Benz ML550 Hood Latch Replacement Cost

The hood of a vehicle is located ahead of the windshield and opens for access to the engine and other mechanical components. The hood is raised whenever the oil needs to be checked or changed, the windshield washer solvent needs to be replaced, or the battery needs to be charged. The hood is secured shut by a locking mechanism called a hood latch.

The hood latch is usually located on the top of the radiator support panel (the structure ahead of the engine and behind the headlights). When the hood is closed firmly, the hood latch grabs onto the striker (located on the hood itself) and secures the hood in place. A release lever in the passenger compartment is connected to the hood latch by way of a cable. When the lever is pulled, the cable trips the latch to release the hood. The latch is spring loaded, so the hood pops up slightly when released. All hood latches will feature a two-stage release. When the lever is pulled, the hood opens partially. A second release lever on the latch itself, usually under the center of the hood or inside the grille, must be tripped for the hood to open fully. The hood latch is nearly always a manual device, rather than electrical, to ensure access to the engine compartment even if the vehicle's battery (usually located under the hood) is dead. Most vehicles have one hood latch, but some employ a pair of latches on the right and left sides of the radiator support.

If the hood will not lock closed all the way when it is shut firmly, the latch may be faulty. Likewise, if the hood pops open on its own, the latch is probably bad. Another sign that the hood latch may be failing is when the release lever inside the vehicle is difficult to pull or does not retract all the way after it has been pulled.

Because the hood on most vehicles opens at the front, vehicle safety is compromised by a faulty hood latch. If the latch releases while the vehicle is under way, the hood will open suddenly, strike the windshield, and block the driver's view of the road. The secondary safety catch on the latch is designed to prevent the hood from opening fully, but if the latch is damaged or corroded, this safety feature may not function properly. A damaged or defective hood latch should be inspected and replaced as soon as problems are detected. A hood with a latch that has failed so that the hood will not close all the way should not be driven, even though the secondary safety latch is closed.

The hood latch should last the lifetime of the vehicle. Dirt, debris, or corrosion can decrease the lifespan of the hood latch. These are a common cause of hood latch failure. Excessive force on the release lever can cause damage to the latch cable and cause the latch to fail.

A simple check of the hood latch release lever will usually alert a technician to problems with the hood latch. If the lever is overly difficult to actuate, or if the lever fails to retract after it has been pulled, the technician will try to determine whether the problem is with the latch itself or with the lever and cable. If the hood can be opened, the technician will inspect the latch for signs of damage or corrosion, close the latch without closing the hood, and pull the release lever to actuate the latch. In some cases, the latch is removed or disconnected from the cable to make sure the cable travels freely in its sheath. If the hood fails to open, the matter of diagnosing and repairing the latch becomes far more difficult.

To replace a hood latch on most vehicles, a technician will open the hood, detach the latch from its mount, unplug the alarm switch if so equipped, and disconnect the release cable. A new latch is connected and mounted and the technician checks for proper operation and alignment before closing the hood. Once the hood is closed, the technician will verify the hood alignment, and adjust if necessary. On some vehicles, trim components may need to be removed for access. If the release cable needs to be replaced, the procedure is markedly more complicated, since the cable needs to be routed behind mechanical and electrical components, around structural body components, and through the firewall (between the passenger and engine compartments) to the release lever location. This can require a good deal of disassembly, and the new cable can be compromised if the procedure is not performed carefully. In extreme cases, if the hood will not open because of a faulty latch, surrounding parts, such as the grille, may need to be broken in order to gain access to the latch.

The hood latch is an essential safety mechanism on a vehicle. It ensures that the hood remains closed while driving - and even during a crash. RepairPal recommends that the latch and cable assembly be inspected by a qualified technician as soon as symptoms show up. If a faulty latch becomes worse, the chance of a failure on the road increases, as does the chance of a hood that will not open at all.

Extreme care should be taken if a hood latch is showing signs of failure. If the hood opens while the vehicle is being driven, a loss of control is possible since visibility is blocked completely. Damage to the vehicle - broken windshield, buckled hood and hinges, and dented roof - is likely.

The hood latch on many vehicles can be replaced by someone with an intermediate level of DIY experience. It should be noted that, not only does the hood latch (or latches) serve to keep the hood closed, but is essential to alignment of the front body panels. The latch must be adjusted so that the hood is in proper alignment to the fenders, headlights, grille, bumper, etc.. If the release cable needs to be replaced, the repair is more complicated and may best be left to a qualified technician.