engine fan only works with a/c on

Is the engine overheating? The fan will only come on if the sensor detects a preset temp. Usually around 180 degrees .... and that's hot

yes with no fan 5=10 min.

I suspect the temp sensor and not the relay because you said the fan does come on with the AC Some temperature sensors are located near the elbow where the coolant goes into the engine

it overheats cause fan won't come on.i installrd new sensor. if i turn on defrost or a/c all is fine