cooling fan

[flyrodd]

engine cooling fan on mk 4 not coming on manual just when gets bout 150 degrees when themo switch closes. WITH SWITCH ON WANT FAN TO COME ON AUTO PLUS SWITCH FOR BACK UP TKS

[CJBergquist]

I'm going to make a guess here. The positive side of the low voltage side of the relay is always hot, or at least when the key is on. The thermo switch completes the circuit by grounding to the engine when the temp reaches 150 degrees. The switch when turned to the on position just gives another path of positive current. I think if you change the switch to go to ground when closed AND move the wire to the ground on the relay you will have what you want. I hope this makes sense.