The Volkswagen Jetta uses an ECM instead of a stand alone fan relay. The ECM has to be changes as a single unit.
A Volkswagen Jetta radiator fan is controlled by a fan relay. If the relay malfunctions the fan could either stay on or not work at all. An engine diagnostic would be recommended.
On top of the battery
it does not have a relay for the fans. they are controlled by the fan control module located underneath the driver side frame rail.
under the hood I guess
Under the. Battery box. It's a. Module
Swap the fan relay with another like relay.
Under the coolant bin, on the right top side of the hood.
Idk. I replaced the thermal sensor on mine I also have a 98 jetta didn't work. So it's either the fan switch or the control module fan relay.
Before you fix the Fan Relay, look for a "RAD FAN" fuse (30 amp - orange). Normally, the computer diagnostic shows the problem is the Fan Relay, but, in my case was the Radiator Fan Fuse ($5). I waste $60 paying for the Fan Relay :-[
The fan relay is in the relay box next to the battery...it says fan relay on it.
If you mean the radiator fan make sure the airconditioning is off. If the fan keeps running it could be a bad fanswitch (located on radiator tank. Or a failed control relay (if fitted) If still no luck check for a failed AC fan control relay.