The temperature gauge is not working on my 2000 S following an engine swap to an engine with a 4 pin temperature sensor. It looks like it is going to take some time to find the proper connector and figure out the wiring details, so I came up with this temporary gauge.
https://www.amazon.ca/dp/B0928QY786?psc=1&ref=ppx_yo2ov_dt_b_product_details
There are 2 sensors so I used aluminum tape to attach one to the boss for the normal temperature sensor
and the other to the rubber coolant tube at the front left of the engine.
I found a use for the ashtray... mounting point for the gauge, dictated by the length of the sensor wires, I didn't want to get into splicing in longer wires. This is a bit of a rats nest... but it is temporary. I took power from my oil pressure gauge which is handy and exposed.
Obviously neither of these will give me a true reading, but I can correlated the readings to the actual temperature seen via my Durametric. So far I have found that the sensor taped to the temperature gauge is only about 10 degrees C below the real temperature. The fans come on at about 106 degrees C at which point the new gauge indicates 200 degrees F... a nice round number to look out for. It is unfortunate that the gauge is only in F, but now I know what to look out for.
elgyqc 
Boxster
Threaded Mode
