So another issue appeared today on my "new" truck (below). I had started the truck, waited about 45 seconds (was driving, parking lot speeds), and as I was in 2nd or 3rd gear, the dash lights turned off, the odometer went away, then it went "ding" and turned back on....

I've noticed over the past few days that the lights in the dash fluctuate in brightness for the first 1-2 minutes of the truck being on and eventually "stay the same". It also affects my radio, which has a flip out faceplate -- when the ignition is on. Sometimes it gets "stuck" and you have to push it's "open" button to get it to finish opening, like the ignition wire went below the minimum voltage...

Ideas?

And yea, the voltage meter has never read below the minimum "safe" voltage (I assume that's 12V). It usually hovers around 14-15V after running for a few minutes, and on cold days when the grid is used a bunch, it can drop towards the low side of the "safe" voltage but never even touches the line...

 

I think the dash lights diming is due to the preheated turning on and off as it warms air for the engine intake until the engine reaches a certain temperature but I could be wrong. Mine does that too but I've never had the radio problem. I'm new to deisel ownership but this is a great place to learn stuff and I'm sure you'll get expert advice from someone more knowledgable.

'06 2500 QC big horn 4X4 with no mods yet other than step bars and spray in lining.

 

Yes the diming of your lights and fluctuating voltage gauge is your grid heater cycling on and off(normal). As far as the odo going away and dash lights going out, I dont know.

 

Aer you sure your dash lights are going out or could they be just dimming due to the reduced voltage?

 

My truck has been fluctuating to lately when its sat over night. I was wondering if it was normal.

 

I was figuring it was the grid heater, that didn't bother me so much....

I'm certain it wasn't just dimming though..
cause the "DING" after the odo DEFINITELY WENT OFF two days ago said, ummmm, I must have an issue... it reset itself. I think I'll disconnect my radio and see if somehow I messed up the wiring (unlikely, I've done radios a hundred times).

I dunno...

 

Ignition switch could be sticking? or have a set of contacts in the ignition switch not making a good connection when cold?

 

Interesting idea... the ignition itself doesn't seem like it's sticking, since I don't hear the starter going longer than I tell it to with the key, but.... where is the dash relay (or relays) (for ignition-12V) located? Perhaps that's the problem..?

 

If you have an aftermarket radio, that may be causing the problem. Also, when you have the truck running, try ever so slightly turning the ignition towards the off position without trying to kill it. You may find that there is a dead spot just before it gets to the point that the engine will turn off. The dash lights will go out, but the engine will still run. I had that happen to me on accident one time when I was getting ready to shutdown, but didn't turn the key but just a little bit. I can't remember, but I think that it dinged at me when that happend.

 

Taco, I just tried your idea and yep, there is a dead spot in the ignition/key itself where it starts to turn some things off (like the fan motors for heat) but not other stuff -- like the radio. Perhaps it is as simple as the ignition contacts. Perhaps I'll take it apart and clean and lube everything... when it gets warmer!!

Sounds like this isn't a super serious thing and I shouldn't be worried my dash is gonna just stop working one day cause of some common defect.

If anyone has any suggestions on a place to look in the wiring for places where connectors often corrode or relays wear out, let me know!
Thanks