Oil pressure sender
 

1984 s2 auto
When I got my car the oil pressure gauge was not working but it now works after cleaning connections, earths etc but it pegs. I suspected the sender and tested it and with the engine off it has a closed circuit. I think it should be open but can anyone confirm please.
Also if I need to change the sender do I need to drain the oil?

I have also just tested the 2 wires that connect to the sender and they are both going to ground. Does this mean I have a short?

If it pegs you need a new one. You do not need to drain the oil to change the sender.
Consider the more expensive VDO sensor as it will last 10 times longer than the aftermarket cheaper senders.

I went out and opened up the 14 pin connector and spread all the pins with a small screwdriver and I now have a correctly working gauge. On the downside the bottom part of the connector is split in half so hopefully they are available to buy

Roger sells the new connector housings as well as the VDO senders