Each gauge has a switch that’s used to access the menu and set the options - the switch is wired into the connector that clips into the back of each gauge so it needed to be located where it would not have to be removed very often so that ruled out the centre console.
My research had taken me to Paul Timson's website (now sadly dead) where he shows how he fitted an SPA boost Gauge to his Mk1 MR2. Paul put his switch in the coin holder in the centre console on the MR2 and after much deliberation I also used the coin holder on the right hand side of the instrument cluster. I had to extend the switch cables so I got some heat shrink tubing and dug out my soldering iron and extended the wires by 15 inches. To run the switch wiring I had to remove the instrument cluster and route the cables behind the cluster – this is made easier if the cables are taped together. The coin holder had a plastic divider to ensure that the coins don’t flop about and I removed this by shaving off a bit at a time with ½" wood chisel. I drilled three holes and mounted each switch – a word of advice – do the middle one first because the lock nuts are a pig to get on in the confined space. I marked each switch with the gauge name before I installed them to ensure that the buttons were installed in the same relative positions as the gauges e.g. the oil temp/pressure gauge on the left and the button is also on the left.
Now to get the gauges wired up for power. As the air con had been removed when the engine transplant was done I decided to take a power spur from the back of the air con switch. Using a multi-meter I found the cable that became live only when the ignition was turned on and soldered a cable onto this. As each gauge is fused separately there is no need to fuse the live feed. I made an earth connection directly to the dash support metalwork behind the gauges. I tested all connections for continuity and checked the voltage across the live and earth before connecting any gauges – better safe that sorry - those SPA gauges are not cheap.