The Voltage on my gauge is changing depending upon my RPM's. It hovers around 14v, but when i'm driving it'll go a bit beyond that. Then when I idle or come to a stop, it'll drop to just below 14v. I don't recall if this was normal behavior for this truck, or if i've only started noticing it lately. I do know that my other cars don't do this, though.

Not sure if this is related or helps, but when I turn the key to start the truck or even put it into accessory mode, it takes 10-15 seconds for the voltage to climb all the way up to 12 volts (not sure if that's normal for this truck). Thinking this was the alternator flaking out (and since it started whining), I changed it, but I'm still having the above problems.

I'm just looking to see if anyone else had similar issues, and if so, what caused it?

 

Normal behavior. Nothing to worry about.

 

Some vehicles have a buffer on the gauges to give a false "steady" read to keep people from questioning it. The oil pressure gauge on my old GMC used to bounce all over like crazy at idle, but that was perfectly normal for that engine. In the newer GM's the gauges all stand perfectly still, but if you take a meter to any of the sensors or alternator, readings can jump up and down (within reason).

 

Whew. Glad to hear this - I guess I got a bit paranoid and only really started to notice the fluctuating gauge after I knew the alternator was going bad.

My 87 Wrangler has gauges that are all over the place. I guess I never really noticed the voltage fluctuation with this truck.

Thanks again.

 

Pretty normal. As long as your lights don't get dimmer every time it is idling vs accelerating.