These batteries (indicated by arrows) supply power to the service reminder (SI) indicator light panel.
Rechargeable NiCd batteries power the computer's memory when power drops (for example, when the ignition is turned on) or in the complete absence of voltage (with a discharged or disconnected battery). This ensures that the computer has a constant power supply so that it can continue to count the kilometers traveled and turn on the warning lights on time.
The service life of batteries is approximately 6 years, after which they should be replaced with new ones. In addition, since they are recharged from the engine system, they can fail earlier for some reason (for example, a blown fuse, damaged wiring, or the vehicle being left idle for too long). Extreme heat or cold can also shorten the life of batteries, especially heat. Very high temperatures can even cause batteries to crack and leak acid onto the instrument cluster components.
Some devices controlled by the SI panel may be affected by weak or dead batteries. Signs that the panel batteries are weak or dead include erratic readings in the tachometer or temperature gauge, background noise in the radio, and the inability to turn off the panel warning lights using a special tool.
Although the entire SI panel assembly can be purchased from the manufacturer, the batteries are sold separately elsewhere. Since the batteries may be replaceable by a home mechanic, they are soldered to the panel so that if you are not skilled enough and do not have the necessary tools, the job can be left to an experienced electronics technician. Significant cost savings can be achieved by removing the instrument cluster (see section Removal and installation instrument panel components) and take it to an electronics specialist.
The instrument cluster and its components are very susceptible to static electricity. Make sure you are grounded and free of static electricity (touch the metal water pipe) before touching instrument panel components.