druck press guage not working properly

On my 78SC the druck press gauge needle rises only to about 3 max .Is there a way to test it to see if its the guage or sender?
Also any ideas on how to repair it?

[This message has been edited by jryerson (edited 01-01-2000).]

You should be able to pull the spade connecter off the sender. I can't remember for sure, but I think when you pull it off, the gauge should read full scale and when you ground the lead, it should drop to zero. That should confirm if your gauge is working right.

thanks Tim
I'll try and find the ground wire I know the green/red stripe is from the sender
Is it the brown wires that run thru the instruments?

I assume from the subject line of your post that you have metric gauges on your SC ... no matter, my '73 'S' has American gauges, but the OEM VDO sender is stamped '0-10 kp/cm^2 and works perfectly. It measures 27 Ohms at 0 psi, so I know positively you could test your gauge in the car by acquiring a 10k or 20k pot (10,000 or 20,000 Ohm potentiometer ... available at Radio Shack) and ground one end, connect up the wiper to your sender lead that goes to the gauge, and when you sweep the pot shaft from one end to the other ... your gauge should sweep full range, 0-10, I presume.


ANYWHERE in your electrical system, a solid brown wire is ground ... allowing for aging of the vinyl, it might appear as anything from a faded Tan to a very dark Brown. But any German vehicle wired according to the DIN standards, Mercedes, VW, BMW, Audi, and Porsche ... all use brown ground wires!

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Warren Hall
1973 911S Targa

Big help thanks Warren
the gauges range is from 0-5 i'll give it a test



[This message has been edited by jryerson (edited 01-02-2000).]