speedo binnacle

[scaligeri]

Anyone shed any light on how,why and fix the speedo, i have brought a 2nd from e-bay and told it was working fitted it today jacked the rear up ran it and guess what still not working.So either the 2nd speedo is knackered or its something else.I have tested the line from the dash to little black box under the rear seat comes up as 0.5ohms on all wires so! any sugestions :? :?

[purple145]

IIRC there are two types of speedo, mine (an early 75 has no black box) and they are not interchangable, so either you have incompatable speedos or that black box (which amplifies the current) has had it.

How old is your car?

(I know I should know, but I cannot seem to get on the 'other place' at the moment)

[scaligeri]

car's on a 86 plate how would the speedo's be different if it came from a car with a black box wouldn't thay be universal

[purple145]

Hmmm, would have thought so, unless there is a wiring fault somehere?

[XAR75X]

Scaligeri

Do you know if the sender unit in the transaxle is OK?
The ohms test just shows the wires continuity is good (depending on what you tested).
From memory the sender units are magnetic and fail with age. The one in my previous 75, the V6, did, and needed to be replaced.

DaveB