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 if you are going to replace it, have the new one waiting to screw in and you wont lose that much coolant.

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 or the wiring to earth. red blue wire is the high speed fan side, red black is the low speed. The centre is red white and comes from the fuse, so this is switched on the positive side. A good place to start is check the earth points above the fuse box with the crowns of earths. http://wiki.club8090.co.uk/index.php/VW_Electrics_bad_earths