Help please

[shagnasty]

hello, i usually figure my problems out myself. on my 85 f-150 having trouble with fuel gauge/temp. i checked all wires for current. thumbs up. i went anyway and replaced pump/sending unit. checked gauge with test light behind the dash. 1 sides a low pulsing light the other is brite pulsing. thought it may be grounded out. replaced the cluster ribbon, still having the same reading. how do i fix this problem anyone know?

 

[84-6.9L]

did you replace the voltage regulator on the cluster as well?