All,
I uploaded a fairly detail post (including some updates in response to questions) on dash conversions, including bulb types and details for dimming control using a low cost (< $10) commercially available electronic variable pulse width dimmer module. The module fitted nicely in place of the original Lucas item or easily hidden elsewhere under the dash panel etc. PLEASE NOTE
- due to the circuit design of this dimmer it does not work well when fully installed in our cars - I am working on a compatible replacement, so on/off only at moment.
Unfortunately the post series was caught up in the post freeze period associated with transfer to the new forum/website and despite some good effort from our moderators etc they were not able to be relocated.
Given a little time over the coming holiday period I will look at regrouping my thoughts and reconstructing the original information.
The illumination bulbs in the instrument cluster are known as type T10. Many varieties available, but recommend use of the Green corn cob style with a max of 9 led elements. This gives good light spread and not excessive bright when used at full brilliance. Anything bigger results in light bleed/overspill and distracting glare, but set them right and they are excellent plus dimmable smoothly all the way down to off. You need to remove the exisitng green caps which can be done from the front of the dash panel (also the bulb change) after partial disassembly (be careful) of the top cover, front lens and black gauge mask. You can also get more common end lit LEDs in variety of colours to use in the warning lights, indicator, high beam etc.
Do not use an LED in the chg/alt/ign warning light. This must remain an incandescent bulb as it forms key part of the alternator initial excitation circuit - LEDs are polarity sensitive therefore unsuitable as current must flow in both directions for correct alternator excitation. There also various styles better suited to the over radio console lighting, but these take a little more effort to install effectively. Rgds, DM in Oz