Help with Speedo wiring cct

[greg356a]

Hello,

Got an issue with getting my 911 speedo to work with the 915 gearbox. Test is next week so urgent help needed. Background is that I am building a Frankenstein 356 speedster with mix of Porsche parts and custom wiring loom. I think its my loom which is wrong.

How do I connect speedo terminals +, 4, 31b and - to the green and brown wires coming out of the gearbox? Anyone have cct diagram? I have done google searches not much to go on some reference a wire from the back of the Rev counter to speedo?

911 speedo refurbished by Reap automotive so that should be ok

IMG_1770 by [url=https://www.flickr.com/photos/149951780@N05/


915 electro-magnetic pick ups refurbished by Mike Bainbridge so confident ok

IMG_1771 by [url=https://www.flickr.com/photos/149951780@N05/

[Mike911scrs]

HI Greg

the wiring is;

+ = ignition live

31b = wire from the gearbox, usualy the green or brown/red

-- = earth, brown, you will need a earth wire AND one wire from the gear box on hear also


A = a signal take off for the Automatic Speed Control, control unit

regards mike

[greg356a]

Thanks Mike,

will connect as described, from memory I think the second earth is missing.