2nd Gen Non-Engine/Transmission Fluctuating Voltage Gauge!

[gerry]

I have a 97 3500 5. 9 Cummins and my question is: I disconnected both batteries and did a good cleaning of the battery tops and the cable ends and the battery posts. Upon putting things back together I noticed that when starting the voltage gauge now immediately goes to about 12v and then fluctuates from there to about 14. 2 v three or four times during warmup. After this scenario the needle stays on 14. 2v until the next startup. Before the post and cable end cleanup it did not do this, what gives?

 

[Timbeaux38]

Where are you located? What is the temp? If your grid heaters are cycling, you wil see the voltmeter fluctuate at startup

 

[gerry]

I`m in Bend, Oregon. Currently slightly above freezing in the morning. If I read right, the grid heaters cycle at temps well above freezing, that would account for the voltmeter fluctuation, DUHHHH!

Thanks,

 

[mhenon]

You can plug it in at night and that will take the drain off the batteries during startup. Those grid heaters are about like dropping a wrench across the battery terminals... ... . dead short!!!

Mike

 

[DieselDoghouse]

Do you see fluctuations while rolling? This would be a good test since the PCM cancels heaters above 18 MPH.