If I go ahead an get the manual fan switch kit would 1 switch turn on both low fan speed & high fan speed, or just high?...

 

I have the SLP manual fan switch hooked up on my car..in the up position the fan is low in the middle or off position the fans turn on at the stock temp. and on the bottom position the high speed fan kicks in.

 

93s dont' have low and high speed fans. They have primary and secondary. Each runs at full speed when it is on. The LH runs first, then the RH, if demanded by temp. A fan switch will turn on the LH one and then add the RH one in the other on position.