Wiring harness for Sun tach?

Someone gave me an old Sun Super Tach II that was working fine when pulled. Sadly, the original owner lost the original wiring harness (4 wires) and nicely soldered four wires to the posts at the back. Even more sadly, all the wires he used are red!! So I have no idea what goes to where. I can see some small letters near the posts that look like G, I, L, and maybe B. Does anyone know what they mean? Thanks!

could be G= ground, I= ignition,B= battery L=light

I happen to have an original installation and instruction sheet for the Sun super Tach II.There should be a T,L,G and B terminal,the T connects to the negative side of the coil,the G goes to engine ground,L goes to dash light circuit,and the B terminal goes to ignition switch or accessory terminal of fuse box.Hope this helps.

Thanks everyone. That's what I needed!