Generator gauges increase when headlights are on

[The Newell]

Before I start tearing into the dash, etc. I have a question perhaps someone has an idea of what to look for. I recently removed the diesel generator on my Newell to build a better sound enclosure. It performs well and all power is fine. But last night while preparing for a trip I ran the generator (with shore power plugged in) and noticed the oil pressure gauge and temp gauge jump up about 1/2 inch when the headlight switch is turned on. I did not change any wiring in the console or move any grounds. All the dash gauges remain at their normal readings and I don't have any fluctuations of power frequency or voltage in any appliances. The coach runs fine with the exception of the cruise control which will turn on and off but wants to accelerate rather than hold speed. That condition existed when I bought the coach and I just figured I didn't need it anyway and since parts are not available I just leave it off. I know that many problems arise because of faulty grounds but I have not seen only two gauges rise like that while all the others remain in normal range. Any ideas would be appreciated.

[larryweikart]

I've had a similar problem for years. Newell told me it was a ground problem, but I, as well as they, have tried, in vain, to correct this problem. It still drives me nuts as I normally pull a large trailer and have always been concerned about overheating and drive mostly by my temp gauge. There are times, at night with the dash air/heat in use, that my temp gauge shows 230+ but is completely inaccurate. I've stopped and had different service centers shoot the radiator with a heat temp gun and found it to be OK. After all of these years of trying to figure it out, I've just learned to live with it, and now drive with attention only to the warning lights. I don't like it but if Newell can't figure it out I don't know what else to do. I even had a larger radiator built to be sure I'm staying cool enough. If you find any solution, PLEASE let me know.

[Major Stan]

It has been my experience that the voltage has to get REALLY low to effect the gauges, there are internal voltage regulators in the gauges so that battery voltage swings will not produce much variations. What does your dash mounted voltmeter do?

HOWEVER--

Bad ground connections can and will cause gauges to go wild, the type of changes you describe are wild.

When my alternator went bad, the battery voltage went as low as 10 volts and I had a very slight meter reading change, temp changed only a few degrees, oil nothing and the fuel gauge slightly.

[fulltiming]

I also experienced gauges changing values when the lights were turned on. Newell added extra ground wires and it significantly reduced, but did not eliminate, the problem. A weak or bad ground can cause very erratic behavior.

I avoid the dash gauges and depend on VMSpc to tell me with digital readouts what is happening to my engine.