BMW LED Key Mod

I own two 20+ year-old BMWs. They are cars that I drooled over when I was younger but couldn't afford. Now it's possible to find very nice examples for under $5,000; my 1988 735i was purchased last year for $1,200, and my 1984 528e for $800 two years ago. They are easy to work on and will run forever if properly cared for, and will easily keep up with more modern cars. Parts are readily available for the DIYer to keep them running. They're definitely not for everybody though; if you need to rely on a paid mechanic to do the work because you don't have the the ability or space to work on a car, you're better off with something else, because these cars do require some regular attention. The payoff is being able to drive a car that was state-of-the-art in its day and will make you grin with its great handling and acceleration.

As great as these cars are, they are still equipped with subsystems made up of 20+ year old technology, so there are a lot of minor modifications that can be made to make them even better. One of the more pathetic items is the lighted keys; originally they were equipped with tiny incandescent lamps that didn't light very well and wafer batteries that didn't last very long. I have a couple of little LED flashlights that were given to me as promotional items by vendors; dandy little items that work well but have been cluttering up the junk drawer in the kitchen for too long.

So I thought it would be good to use the LED lights as donors to convert the key lights to get longer battery life and better light. It was pretty easy, didn't take very long, and the end result works really well; well worth the time.

Step 1 First Step...

... is to dissemble the key to see what you have to work with. This key, from the 735i (e32) comes apart by pushing in the button then using a small screwdriver inserted into one of the gaps to pry the light assembly from the housing. Then the screwdriver was used to release two tabs that kept the light assembly together. After that, the parts of the actual switch could be accessed. Of course, I pulled it apart without taking note of how things were arranged, so putting it back together was a bit of trial & error to see what went where. Next time I'll take a photo of it first!

Comments

[spike1167]

Do you know what batteries these were? Like what model? (Example, the old battery is a CR[followed by 3-4 numbers])

[davintosh]

No I don't; sorry. They were just the batteries that came with the LED flashlight. If you've got an LED that didn't come with the batteries, you could just pick some batteries that were the proper diameter, thickness & voltage. Keep in mind that the LED's typically need 6V to operate properly, so a pair of 3V batteries works great.