LED keyhead transformation:

Keyhead bulb to LED conversion.pdf


you first have to detach it from your key ring. Then you pry open the cover and take the button,  battery and the little brass strip between the battery and the globe out , then look  down towards the keyshaft and to the right, you will see a little spring.

this spring is holding tension on that little strip of black plastic that you can see also. What you have to do is clamp the key shaft to a table then with a sharp hard object push that plastic strip towards the spring, when you push it hold it there and at the same time wriggle the keyhead off the keyshaft. When you pull it apart you will see how it all held together..
Pretty smart I say :)

hope this helps


I just did this as the previous owner of my new shark had purchased the key head and hadn't put it on one of his non-lighted, crestless keys.

You just use your thumbnail to lift off the top where the button is.  Then take a pointed object (I used the tip of my scissors from my tiny Swiss knife) and push the small shim toward the spring while pulling at the key portion.  I just had my wife hold the key with a pliers while I pushed the locking shim aside and pulled.

The metal key will slide right out, without damaging the old key head (aside from a small mark on the shim inside).

Now, just slide your key into the new key head with the notch on the key on the same side as the locking shim (side away from the light).

Mine looks great...light AND the crest.

David Schmidt
'90 GT, Guards Red, guy with BIG grin driving.

The black key head with light is designed to be removable and replaced ; new battery , bulb , and crest # 944 538 041 00 Porsche # about $15

Jim Bailey

Hi any idea where I can get a replacement bulb for my ignition key, I replaced the battery but it still doesn't work so assuming its the bulb.
Any help appreciated.

Sometimes the bulb in the keyhead fails. Here's a LED replacement instruction for the 928 Porsche keyhead


I used this source for the key mod: http://p-car.com/diy/key/ , but I found the polarity incorrect in the instructions (I submitted a correction a few months back). Instead of "The short post goes to the battery, and the long post gets wrapped securely around the copper pole." it should be "the LONG post (always positive on LEDs) goes to the positive terminal on the battery, and the SHORT post gets wrapped securely around the copper pole."
I found the end results were amazing though - very bright!

'89 928 S4 GTish



Try Maplin, they carry a pretty good selection of bulbs. You'll need to know the voltage 1.5v I looked up Varta V625U battery on google and the power (watts or maybe maybe 100s of milliwatts) or the Current rating - then take along the old bulb to match the shape. I looked at my bulb but it says nothing on it.

If you feel adventurous do a search on rennnlist 928 forum for Jim Morehouses instruction on how to replace the bulb with a LED.

Jon in NZ

I converted my key to LED. Itís about 1000 times brighter, the batteries should last up to 10 years, and the light is claimed to be visible up to a mile away. The whole job took less than an hour and cost about $10.00. Hereís the process and the supplies needed:
1. Two CR1620 Lithium batteries (3VDC each).
2. One LED bulb, I used one from Radio Shack (P/N 276-311). Itís rated for 5VDC typical with 6VDC maximum. They come in clear, blue, red, green and infrared.
3. A 5/8Ē rotary file (pictured). The original battery is 15.5 MM wide and the new batteries are 16 MM so you need to enlarge the battery compartment in the key.
4. A #60 drill (that was the smallest I had) for one of the bulb contacts.

1. Disassemble the key: remove the copper strip and the copper ring at the bottom of the key, the small spring in the center, and the old bulb.
2. Drill the #60 hole in the tab of the copper ring anywhere near the center.
3. With the rotary file enlarge the battery compartment. Do this by hand! The plastic is too soft to use a drill press. If your alignment is off, the rotary file grabs the key and destroys the hole. It took less than 10 minutes by hand.
4. Re-install the copper pieces and the spring.
5. Install the bulb with one contact through the hole you drilled and the other contact pushed up against the copper strip. You will have to cut the contacts to length.
6. Install the batteries, neg. side down. The batteries will bow out the copper strip to keep contact with them and the bulb.
7. Re-install the key button and the cover. The button no longer fits over the battery, but the height is the same as the original installation.

Once assembled, there is no difference in the appearance of the key, until you turn the light on.


These are the original battery and bulb: