Where is the glow plug relay on 1990 Isuzu trooper?

The glow plug relay on a 1990 Isuzu Trooper is typically located in the engine compartment, near the battery or on the driver's side fender wall. It may be housed in a small plastic box or mounted directly to the fender. For precise location, consult the vehicle's service manual or look for a wiring diagram specific to that model.