Coolant and Heating Testing radiator fan

The connector to the radiator temperature sensor is on the lower right side of the radiator looking from the front of the van Remove lower grill and try not to loose the expanding plastic clips, you can use a large adjustable spanner to unscrew the sensor. The electric connector pulls off and has three female spade connectors, jump the middle pin to each of the outside pins in turn (use a big paper clip), one side should bring the high fan on and the other should bring the low fan on. if one side or the other doesn't come on there is likely a fault with the fan. If the high side comes on and not the low you can rewire your fan so the high fan comes on at low. It will run noisier with the high fan speed but to be honest it is very rare that the high fan comes on in normal operating.