What is the No. 648 relay in Volkswagen Lavida?
3 Answers
Volkswagen Lavida's No. 648 relay is the main relay, whose primary function is to control instrument power supply. The relays used in automobiles switch high load power and feature high impact and vibration resistance. Automotive power systems mostly use 12V, with coil voltages generally designed for 12V. Since they are powered by batteries, the voltage is unstable. Under harsh environmental conditions, the pull-in voltage V≤60%VH (rated operating voltage); the coil overvoltage can reach up to 1.5VH, and the coil power consumption is relatively large, typically 1.6~2W. Below is additional information: 1. Composition: Automotive relays consist of a magnetic circuit system, contact system, and reset mechanism. The magnetic circuit system includes components such as the iron core, yoke, armature, and coil. The contact system comprises parts like static reed, moving reed, and contact base. The reset mechanism consists of reset reeds or tension springs. 2. Contact resistance: The contact resistance present between the relay contacts in automotive relays mainly consists of constriction resistance and surface film resistance. The contact resistance is related to factors such as the contact form, material properties, and surface processing. Therefore, to reduce the contact resistance of relay contacts, under a certain contact pressure, improvements can be made by optimizing the contact state and enhancing the contact materials.
A while ago, I encountered a no-start issue when driving my friend's Lavida. After struggling for a while, I found it was caused by a faulty 648 relay in the fuse box. This relay is the critical component specifically controlling the starter motor. When you turn the key to ignite, it connects the current to activate the starter. In Lavida models, this relay is typically located in the engine compartment fuse box with a clear marking "648". If it malfunctions due to issues like contact oxidation or coil short-circuit, the car won't start, though other electrical components may still work normally. I'd recommend owners not overlook this small part - regularly check for looseness or aging signs during maintenance and replace it promptly if needed. This simple precaution can prevent unnecessary trouble and save you a wasted trip to the repair shop.
The 648 relay in the Volkswagen Lavida typically serves as the starter relay, responsible for amplifying current to drive the starter motor during ignition. It is located in the engine compartment's fuse box, labeled '648', and functions as an electromagnetic switch. If it malfunctions, common symptoms include the starter motor not turning when the key is turned. Possible causes include contact erosion or dust accumulation leading to poor connectivity. Repair is straightforward: first, check if the fuse has blown, then remove the relay and gently shake it to listen for abnormal sounds, or simply replace it for testing. It is recommended to use genuine parts for reliability, and regular cleaning of the fuse box to prevent dust can extend its lifespan. In fact, relays have a long lifespan but may degrade with the vehicle's age. Understanding its function can prevent unnecessary spending on other parts.
