Fuel Gauge not working...1989 XJS

In looking for solutions for my ABS issues, yesterday I cleared the boot and went looking for causes to extinguish the amber dash light. This morning on starting the vehicle I noticed the the fuel gauge not registering when I knew I had gas in its belly. I wonder if I nudged or disconnected something in the boot. After doing research, I saw a picture of the 3 wire sender. I removed all the wires and cleaned them. Nothing. I removed the dash cluster and chequed the system…all good. I don’t think there are any fuses but I chequed them anyways…nothing. I ran across a part called an anti-slosh module, but don’t know if that was installed in the 89’s. Can’t find it anyways. The only thing I am not sure of…next to the ABS module on the left trim is a lonely black relay. I don’t know what that is hooked to…it sits adjacent to the ABS module.
Question is, what went wrong? And is the anti-slosh relay pertinent to my vehicle? What is that lonely relay next to the ABS module.
Tomorrow I plan to spend the day doing what it takes to rehabilitate the vehicle and any of your input will help.

I am not knowledgeable on the fuel gauge system, but the sender is easily accessed in your car, behind the spare tire, and might be the best place to start troubleshooting…
I’d advise you to search this forum for previous posts about fuel gauge issues.
For example: [xj-s] fuel gauge problem - #3 by gregory_wilkinson-ri …reply by gregory wilkinson describes some simple tests to determine if the sender is operating properly.

Yesterday was the first time I noticed it not working. I knew I had a 1/4 tank for the holiday weekend and was planning to fill it. Thinking perhaps the float was stuck, I filled it and still had no movement within the gauge. Cleaned the 3 terminals and still nothing. Today will perform electrical tests. This is a new issue, never had trouble before.


Good news.
This morning I dug through the wires and found a short which I fixed and the fuel gauge is working.
Thanks to all those who sent me ideas.
The only other issue is to get the amber ABS light to turn off.

As I mentioned in the other thread, you need to replace your Black Top ABS Combination pressure switch with the AC Delco 25530882

Good news!
I traced the wiring on the fuel pump and found a short…issue resolved.
Better news!
The speedometer and odometer. I dismembered the dash cluster and cleaned the PCB board thoroughly and made sure I had valid grounds. Still nothing. I chequed the speed sensor in the boot…it was good…THEN…I removed the three circular plates in the back of the boot and found the issue. The gray cable was pinched and slightly severed. Being a ham radio operator, the cable reminded me of coax. I cut the cable and stripped back the two wires, one red and one blue, and cleaned the shield. Carefully, I soldered the wires back together, wrapped it heat resistant silicone bonding tape and took her for a test drive…issue solved.
Productive day.