911SC Cruise control

[Renos]

I changed the speedometer on my '78 911SC and the cruise control stopped working. The new speedo (correct part # for the year) is calibrated in kilometers per hour(and it works fine as such) whilst the original one is in MPH.
The Porsche parts book gives the same control unit regardless of the speedo type or the year of the car. I also checked that there are not different types of speedo for cars with or without C/C.
Reverting back to the old speedo makes the C/C work.
Any similar experiences or ideas as to the possible cause, please?

[This message has been edited by Renos (edited 08-03-2001).]

[Wayne 962]

I don't think that they two are related, unless you pulled out a wire when pulling the speedo out?

-Wayne

[Roland Kunz]

Hello

The speedo is just a rev counter. It als will count lightspeed if you make a scale for it. Well a good Porsche can reach 0,0005% off it.

Just check if you hooked up the wires correct. See pelican tech section wire shematic 3,0 SC.

Grüsse