87 745T. Often times (not always) the Voltmeter will read just above the red (10), as if the alt isn't charging well. After driving awhile it slowly climbs to mid-point. At night with lights on, it will drop into the red. The more accesories used (fog lights, fan) the more it dips. I replaced the voltage regulator a few months ago with a Dave Barton adjustable - it made no difference. Never though has the car displayed any symptoms of low charging, such as dimming lights, weak blower fan, squealing belt, etc. Car always has run fine.

So last night I start the car, VM barely moves above red, then for some reason I decide to adjust the dash panel brightness. Lo and behold, as I dim the panel, the voltage meter climbs! Sure enough, the brighter I set the dash lights, the lower the voltage (displayed anyway) and vise-versa. By keeping the dash lights almost all the way off, the voltmeter reads just to the right of the mid-point.

Anyone had this issue? Might I just have a bad ground behind the dash or something simple like that?

TIA