Hi - this can be done without soldering. Easiest place to do it without it showing is at the DME since you have to conceal the DME and relays anyway. Not sure if RHD cars are the same as LHD, but, if so, the DME is normally in a cubby in engine compartment on the drivers side in RHD car. There is room there for the Tach Adjust component to fit. Wiring is easier at the DME, because there is already power and ground wires there to tap into, and you just need to identify which wire coming out of the DME is the Tach signal. Some notes: 1) Find a power wire that is Switched On with the ignition so the Tach Adjust is only on when the car is. Use the Electrical Troubleshooting Manual/wiring diagrams for your car to see which wire to use. 2) For power and ground, you want to "Tee" into the existing wires 3) For the tach signal, you want to "break" the wire so that Tach Adjust sits in-line with it. The DME side of the wire goes to Tach Adjust input, and Tach Adjust output goes to the side of the wire going into the harness (which will eventually go to the Tach). 4) I'm using "Tach Adjust" as the example, but any tach signal converter will need the same connections. 5) This can also be done behind the instrument cluster, because there is switched power and ground wires available there too, and you put the Tach Adjust in-line with the Tach signal going into the cluster. I'm not sure if this helped... the ETM/ETK will be your best resource to find the right wires. Happy to answer any questions. Cheers, Drew __________________ Bimmers: 90 325i, 96 318ti (330ti), 02 530i Beemers: 93 K75s, 96 K1100RS SE Jeeps: 01 Wrangler TJ 4.0L, 19 Wrangler MOAB 3.6L |