If you want a copy of Classic Roadsters’ schematics, let me know. I have my complete assembly manual.
An alternative somewhere between MGMagic’s “complete” and starting from scratch…search for Dune Buggy wiring harnesses. They will have most of what you need.
Here is one example, http://www2.cip1.com/ProductDetails.asp?ProductCode=ACC-C10- 5720. This harness includes color coded looms with fuse box and connectors, allows for headlights, tail lights, turn signals, dimmer switch, license plate light, gas gauge, speedometer, windshield wiper, starter switch, horn and voltage regulator. It’s less than $55. You would have to fabricate wiring for other gauges and lights for them. There’s a link to the wiring diagram for this harness on the above page so you can see what you are buying.
Godo old JC Whitney has one too, for about the same price http://www.jcwhitney.com/webapp/wcs/stores/servlet/Product?s toreId=10101&Pr=p_Product.CATENTRY_ID%3A2001329&prod uctId=2001329&catalogId=10101
Like many of the things we do…your choice is between $$ and time.
Lemme know about the CR diagrams.
Former Owner of a 1981 Classic Roadsters Ltd. Duchess (VW)
2005 Intermeccanica Roadster
If you own a TDr and are not in the Registry, please go to https://tdreplica.com/forums/topic/mg-td-replica-registry/ and register (you need to copy and paste the link)