XxHellaFlushRB20xX

i recently bought a 1991 240sx cp that has a RB20det swap, the wiring was terrible, break lights didnt work, reverse lights dont work and speedo doesnt work. i managed to rewire the break lights but the reverse and speedo still dont work. any ideas why? also aacouple days ago the engine started to leak coolant from somewhere in the back of the block thats dripping down onto the transmition but cant find exact location. i was told it could be the coolant feed to the turbo, the plastic fitting in the pipping. could this be the problem? And it will not start now