How to Replace the Key Battery for an Older BMW 7 Series?
2 Answers
Steps to replace the key battery for an older BMW 7 Series: First, press the button on the side to remove the mechanical key, then insert it into the groove on the back cover. Gently push to pop the back cover open. Replace it with the prepared new battery, then close the back cover and reinsert the mechanical key. The battery replacement is now complete. The older BMW 7 Series measures 5223mm in length, 1902mm in width, and 1498mm in height, with a wheelbase of 3210mm. Compared to the previous generation, the length and wheelbase have increased by 30mm and 80mm respectively. The enlarged dimensions achieve a sporty exterior design, while the long-wheelbase model features a 140mm longer wheelbase compared to the base model.
My old BMW 7 Series from around 2000 required some tricks to replace the key battery. There's always a small groove on the back of the key - use a flathead screwdriver or thin plastic tool to gently pry open the casing, being careful not to crack the plastic. Inside you'll find a CR2032 battery, a round coin-shaped one. Pay attention to the polarity - the flat side facing down is the positive terminal. When removing the old battery, avoid touching the contacts with your hands to prevent static damage. Just pop in the new battery and press it flat. I've done this several times myself, saving the hundred bucks or so it would cost at the dealership. Normally the battery lasts 2-3 years - when the signal weakens, replace it promptly to avoid door locking issues while driving. The old BMW key design is relatively simple - just pick a well-lit area when prying it open, take your time, and don't rush, as damaging the key would be counterproductive.
