I just got my '97 Wrangler Sahara a few wks ago, noticed a clicking noise and found it was, just like yours the signal relay.
Got a new one (for $18) at Napa, but it wasn't the problem. I did some troubleshooting but quit after a couple hrs. The previous owner added some hokey looking wiring onto a trailer hitch and that's where I stopped.
This next part is embarrassing to admit, but I ended up extending the wiring and re-locating the clicking relay under the hood on the left-front fender!
When I get more time I'll continue to troubleshoot but at least for now that damned clicking can't be heard
If you like I can email some schematics to you, just write to: firstname.lastname@example.org