To check the solder joints you need,

Allen key - 4mm
Torx bit - T7 or T6
Soldering iron
Soldering wire
A steady hand
A good light source

1 - Take off fuse box cover
2 - Take of bottom steering cowling
3 - Unclip the motor wire from ECU
4 - Unbolt the motor, theres 3 hex head bolts, here you can use 8mm socket
4 - Take out motor and boss - leave boss in car as not to loose it
5 - Take off foam gasket (try not to rip it, if u do, dont worry)
6 - unsolder the 6 main wires beside each relay
7 - unscrew the 4 torx screws
8 - take out circuit board
flip it over and resolder all connections on relay, on each theres 3 main and 1 smaller one
9 - make sure you have plenty of solder on each one
10 - then reattach to motor, screw in 4 torx and bracket
11 - resolder main wires, you may have remove old solder to get wires back in fully
12 - reattach foam gasket
13 - reattach boss
14 - bolt back into place
15 - reconnect wires to computer

Then put key in, cross your fingers and start the car.

If it was a bad connection that was causing it, hopefully it will be fixed now.

Hope this guide helps someone.​