Before I crawl under the dash

I've been really happy with the M&H wiring in my other two Darts, so while it's possible, it isn't likely. A faulty IVR seems like a possibility. Is it OK to momentarily jump the IVR to see if the gauges jump? I assume I can ground the unit to the frame and if that works install a permanent ground wire. I'll try stuff tomorrow and let you know what happens. Thanks for your time and expertise.