I've just obtained a tacho from a 1984 HJ47 being wrecked... only problem is my 1981 HJ47 was never fitted with a tacho. I read in some threads that there may have been a spare plug behind the dash (apparently Toyota used the same wiring harnesses regardless) but I couldn't see one
. Can anyone tell me what it hooks up to? Or a wiring diagram?
I've fitted it to the dash but it's just not operational.

