The wiring diagram confirms your relay is in the IPM (fuse box). Doesn't give the location on the panel though. There is a 40 amp fuse that protects the rear defog/defrost and an 8 amp circuit breaker that protects the mirror defog/defrost. If you eventually change the relay without success, the Front Control Module (FCM) attached to the IPM controls the ground for the relay.
******** We took the time to answer your post. Please give us some time and post the fix. You'll help hundreds. ********
**** Follow all prescribed safety procedures before attempting any repairs. If in doubt, refer to a maintenance manual. ****
96 Gr Caravan LE 3.8, 212K miles
07 Fusion / 06 RAV 4 / 06 Accord