RW defroster stopped working for this season.

1. Light on switch comes on then goes off by itself like it always has but but no defrosting action is taking place.

2. At the beginning of the next driving cycle when the key is first turned on (but car not started) a clicking sound can be heard coming from behind the dash briefly then stops, car starts normally. Only happens when I attempted to use the defroster during the previous driving cycle - not at any other time.

Owners Manual doesn't show a fuse but it does show a plugin relay at the #29 position inside the underhood fuse/relay box. The connections at the rear glass look good with no broken wires, etc.

Unplugged the relay, cleaned the 4 blade connectors - no difference. The clicking noise seems to be coming from behind the dash but I'm wondering if its actually coming from under the hood?

Will run this scenario through multiple Mustang forums attempting to get the best possible sample of responses. Thanks in advance.

 

Did you have your rear glass tinted? Replaced the Tint? If so they could have scraped the conductors. The clicking only happens then the rear window defrost is on? Nothing else?