Edited: another fuel/temp gauge thread, but turns out the harness is melted together

Both gauges havE a regulated source. The IVR is nothing but a flasher. 1 sec on, 1 sec off. Averaging to half the supply voltage. Slow responding heated spring wire gauges are not “meters” and respond slow Put a LM7806 three leg voltage regulator in place of the “5v regulator flasher”
I’ve done it , works great.