AC electrical connection

[Jastx]

As part of an AC upgrade I'm doing on my 930 -- replacing evaporator, condenser, hoses, drier with the latest-tech equipment, I need to hook in a high-low pressure switch connection in the compressor circuit as part of the R134 requirements.

See the pic below. My understanding is this hi-low switch (which in my kit is built into the new drier) connects inline with the compressor circuit to cut it off if the pressure gets too high or too low. I'm told, unverified, that the yellow wire in the pic is the one that should be cut and spliced to the in and out wires coming from the switch.

This may sound stupid but bear with me... I don't like modifying factory stuff unless it's bolt on and can be returned to factory. I really don't like cutting the factory wiring harness. What I'd like to do is create a small "bridge harness" to connect to the female relay plug from the wiring harness with a complementary male plug (like the relay) with a short set of wires to another female plug which then plugs into the relay. The wiring from my switch would be connected through this "bridge harness" keeping the factory harness intact.

Can anyone tell me if these plugs are available and where? Also, if you have a wiring diagram for an '89, can you tell me which of the wires running to the relay is the one I need to run through my hi-lo switch to turn the compressor on or off? Is it the yellow one?

Thanks!