I have a Gen 4 screen John deere rate controller & swath control. This is on an older sprayer with raven controls. Worked flawlessly last time I used it two months ago. Started spraying today have product at tips but rate controller shows no flow or GPA or GPM with product flowing. Checked flow meter it was not plugged. However cannot determine actual application rate, swath cutoff or mapping. its as if the rate controller doesn't know where the tractor is.