Why does VW use ground wire for radiator fan?
VW added a ground wire to the fan, why because the fan is mounted to a shroud, that is bolted to plastic radiator tanks. These plastic tanks are an insulator, and will not conduct ground. The above is a/c equipped cars, the radiator fan switch also acted as the “After Run” fan switch Simple is more better.
What’s the jumper on a Volkswagen radiator fan?
Jumper 12V+ to the RED/BLK wire one at a time to +12V if the fan runs on both hi/low speed your fan is good. Reconnect the connector, and now measure for a good ground via resistance to the Brown Plug or the Case of the fan. 0 or .5 ohms, then you are ok, infinite, then you better get a new ground.
What does the Shroud do on a VW radiator?
To prevent that, VW placed a shroud over the radiator to duct air over the radiator from the outside. These shrouds aren’t a tight fit. also keeps the radiator pulling air from the Grille. You can make replacements out of sheet tin, brass, formica these are more durable as replacements.
What to do if your radiator fan is bad?
If your fan runs, then your after fan run switch is bad. To test the Radiator fan thermo-switch you have to drain the cooling system, and remove the switch from the radiator. Connecting the leads of your DVOM to the switch legs in resistance mode.
Why does a VW use a single speed fan?
VW originally used a single speed fan, that was simply controlled by a switch in the radiator. They applied 12V+ from the battery to one side of the switch, and the other went up to the fan. Since current needs a path from ground to a source. VW added a ground wire to the fan, why because the fan is mounted to a shroud,
Why does my Audi A3 fan run all the time?
That 4-pin refrigerant pressure switch was a common failure on the A3 cars, and its failure mode would cause the fan to run constantly. Never seen it manifest itself in the same manner on an early A4 car, though, but that doesn’t mean it couldn’t happen.