speedo help

[carlo rossi]

the speedo only works when the engine warms up ( or gearbox)
I  gather its a crack or bad connection
anyone with experience in this
and is there a fix

[MD]

Carlo,
A few possibilities:-
1.The electrolytic capacitors are leaking from old age and take a long time to charge up to value. Change all capacitors with the same values.
2. The circuit  board could have dry joint issues in which case re-solder all connections.
3. Clean all connectors in the circuit from the sender to the speedo head. Be sure the male and female contacts make a firm electrical connection.
Finally, it could all be the result of your alternator building up the charge in the battery to provide a high enough voltage to overcome all of the above and losses around the loom. If after you do these measure and it still is doing the same, there may be issues evolving with the chip on the board in which case you a screwed-they are unobtainium.
Plan B is even more stuffing around.

[carlo rossi]

thanks ill try that in the mean time I bought a new sender unit Ill R and r it and fix the old one as well