Gauge voltage drop with headlights

[flitcrew]

I recently bought a 2005 Holiday Rambler Ambassador 37 ft diesel and noticed on a recent trip that when turning on the headlights the voltage dropped 1 volt, the temp gauge rose 25 degrees, the tach dropped 100 rpm, oil pressure dropped 20 lbs. Only drove it at night once and didn't notice the issue. Headlights worked as advertised. Recently the dealer put in a new backup camera, that's been the only change. Anybody got any thoughts on the issue? Sounds like a grounding problem to me.

[450Donn]

Sounds pretty normal. But to aleviate your concerns, have the battery and alternator tested.

[twinboat]

Yes, a grounding problem. The dash light bulbs are drawing some power thru the dash ground, leaving you with a low voltage situation.

If the had the dash out while doing the camera, I'd be looking there.