I tried to stay away but just couldn't.
2001 DRV 3500 5.9L
So I'm driving along and my warning system beeps to short dings. I look to the dash for a warning light and there is none [[UPDATE- "check gauges" WAS on- I thought the piece of tape I cover "check engine" had fallen off]] but the alternator gauge is on zero. I pull over, pop the hood and the drive belt & alt pulley are spinning fine. Engine off and the wires/connections between the alt. & 1 month old battery are good. Turn the key start up is strong and now the gauge works fine??? Repeated good start up several times gauge reads good.
This just happened and I'm on a "road trip" so I'd like to head off a dead van whereas at home I'd just drive it till it conks with my house to stay in instead of taxi back and forth from shop to a motel.
Any possibilities would be appreciated.
I should add the I've wired (heavy 4g copper) a second battery for vent fans when parked behind the drivers seat. I haven't hooked up a relay yet but just hook the terminals up by hand when driving and unhook when parked. This method has worked for thousands of miles and start up and gauge work when aux. bat. hooked up also.
one last thing- I put a new bat. in a month ago cause a diagnosis showed only 450 cranking amps on my old one. It was starting a bit sluggishly and that old bat. is what I use now for my aux. bat.
Thanks

 

Question becomes, is it actually not charging? Or is it just a gauge issue. Given that the gauge drops to zero, even though the engine is still running..... I would lean toward a bad connection somewhere. Not sure about the vans, but, on the trucks, I think the cluster gets its cue what to displace via the data bus.... so, the PCM is what is telling the gauges what to display. No idea what conditions are required to actually set a code, and turn on the CEL.... but, I would think the PCM seeing 0 volts would certainly get it's attention. Do you have a scanner you can keep plugged in?

 

UPDATE- "check gauges" WAS on- I thought the piece of tape I cover "check engine" had fallen off. Every thing OK for many miles. Bought van used and looks like 1 of the 3 PCM connectors was a little lose with a busted connector holder. Zip tied all 3 tight. Hope that's it. I do have a code reader if that's called a "scanner" also.
Thank you Hey You

 

Yep, code reader is pretty much the same thing, provided it can read the data stream from the PCM. If the gauge freaks out again, use the scanner to see what the PCM thinks bus voltage is. Should be right around 14 volts if everything is working properly.

 

I've had the same thing, it was the screws that hold the computer to the firewall inside the engine compartment.They are a metric thread maybe longer than three inches, dealer didn't seem to be able to provide them. So I used full thread sheet metal screws, trying not to overly strip the original metric thread, which only go through a sheet metal piece so it's only a couple of treads. I'ts loosened more than once, its the same symptoms you describe. A proper fix would require removing the computer and any nearby wires or non-metal parts and welding nuts directly to the sheet metal. The nuts would need have the hold location ground of any paint to assure a good weld and proper electrical conductivity. I will acquire bolt/screws to match the nuts I use, assuring the computer will be tightly mounted. The welded nuts will need to be painted so a not to rust in a few years and give these problems again.
So for now just check the screws for tightness, if the screws are lost find long enough to replace the missing ones and make sure all screws are tight. I am assuming there is a ground connection these screws make. Now that you have secured the screws ( the belt), you could also mount an additional wire between the case of the computer and the body metal on the firewall.( the suspenders)