I have noticed that there have been a number of threads started about this problem. I wanted to put out a solution I have found that seems to work on my truck. Just did this today actually.

Every so often my WTS light, as well as the water in fuel light, stop working. It has done this at least 3 times over the past year, since finishing the 4wd conversion on the crewcab and switching to the complete 93 system.

What I have done to rectify the problem...at least for a while...is to disconnect the battery, both positive and negative cables, for at least 5 minutes. Hook them back up and everything seems to work fine again.

Hope this works for others as well.

 

Have you tried checking the connection pins on the back of the info panel. They get loose since they are crimped. I had to solder mine in place, otherwise my WIF light would come on with every bump.