factory voltage gauge on dual alt trucks

[imported_]

I have been running dual alts for about a year and had my voltage jump on my gauge from 14v up to about 16v last week. No fluctuations at all. After the dual alt upgrade my truck sat at 14v ALL the time. I took it in for service at the dealer and everything checked out OK. (i think) The alts are testing at 14.6v and 137amps at idle. The batteries had 810cca and 816cca. They also did a load test to 380amps at 9.7volts and a starter draw test of 480amps. My gauge still reads about 16v.

The service writer wrote:
"Voltage shows above 14 volts on the gauge but nothing to worry about because actual is 14.6 volts which is perfect."

I thought, OK, all is well, drove off the lot and made it about 1/2 mile before I turned around to ask the dealer for a new gauge. Fifty thousand dollar truck, the voltage gauge should be accurate. Or am I wrong? The dealer went into a rant about how the gauge is linear and how it is there only as a guide. He is really bucking me on getting a new instrument cluster. I asked if the truck does see 14+ volts how am I to know? Isn't that the purpose of the gauge?

What is the best way to monitor dual alts and should I insist my dealer change the instrument cluster?

[BigLakeDMAX]

Brad,

I added the 2nd alternator about two weeks ago. My dash volt guage read about 16v before the 2nd alternator was added and still does now. I've checked it with my own volt meter from time to time and it's at 14.6v. It bugs me just a little that the guage doesn't read correctly, but to have them fix it means, as you indicated, removing the instrument cluster and sending it in. I prefer to not have my dash torn apart and reassembled, perhaps with a reconditioned instrument cluster off of the shelf from the repair facility. And, there's no guarantee that one will be any better. So, I'll be watching the guage for any change from what it normally reads to warn me of a possible problem.

One thing I have noticed with the addition of the dual alternator is that the voltage recovers very quickly on a cold start. It used to drop to below 12 volts (by my inaccurate dash guage) and sit there for a minute or so while the glow plugs and intake heater were energized. Now, it climbs to its customary 16v reading within seconds of starting. Nice addition, I think.

Good Luck!

Don

[IndigoDually]

The gauge on my '94 has always read lower than actual voltage.
I never really got that anal to check the one on my D/A.

John

[a64pilot]

Factory gauges are inaccurate and IMHO are only good for spotting trends. For $50,000 I would want it fixed too. Probably the best thing to do is to pull the needle off and put it back on where it reads correctly. Doesn't fix the inherent inaccuracy of the gauge, but it is probably all you can do.

[Maverick]

My 2500HD has a 105 amp and it reads at 14 or less all the time. My 3500 has a 130 amp and reads 3 ticks over 14 all the time. This is normal as you have said, the gauges are inaccurate.

[oyazi]

Mine always reads 2~3 tics passed 14, even after installing the second alternator.

[battmain]

More curiousity question than anything else. Would it be possible to just reposition the pointer? Reason I ask is because I've read about guage swaps and one of the problems those folks run into, is properly repositioning the guage pointers after the swap. Wonder if maybe the pointer wan't put on properly from the factory. On the other hand, a warranty is a warranty!

[imported_]

As a good will on my part, I repositioned the needle on the guage myself. Seems to work fine. The dealer had settled on getting a new cluster but this is how I see it. They needed my truck to pull the cluster and get the numbers for GM, they would order the cluster and replace my old one. Two days without my truck, not acceptable this time of year. So, after my dealer agreed to change the cluster, I offered to adjust the needle myself. They said sure. Funny thing is that they haven't given me grief about my truck in a while. (been back twice for rear seals) Plus they refilled the dif with mobil syn at their cost. Usally every time in I hear about the gauges, the tires, something, but not anymore. And now the head service writer takes care of me exclusivly and the techs in the back always come out to say hello and ask what new gadget I have for my truck. I think they finally realize I am not trying to screw them, I just want it done right.

[ 03-25-2003: Message edited by: Big Blue ]</p>