You can buy a VDO pressure sender with a warning switch built in, if you want to go that way. That is what I did as it simplifies things. Unfortunately, you do still need something to get the sender away from the filter housing as it interferes with the oil cooler thermostat assembly, so buying a new TEE as Matthew links to is cheaper.
I assume the oil pan has the temperature sender.
Pissing people off on the "net" since 1983.
Land Rover. Turning owners into mechanics since 1948.