[gavetgp84]

06 3500 diesel 4x4 mega cab. I'm having an issue somewhere. When I start my truck my voltage is at just above 12 and then it rises to almost 15. Then about 30s to 1m later it drops back down to just above 12. When it does this my interior lights dim and my dash lights dim. Also it seems like the idle changes a bit for about 1/2 a second (almost sounds like it bogs down really quickly). It does this for the first maybe 2-3 min. If I shut it off and then restart within a couple of minutes it doesn't do it again but any longer than 10 min is does it every time almost. I've had my batteries checked and I've replaced my alternator. I replaced my TIPM about 6 moths ago (had an issue with it not connecting to the PCM OR ECM due to corrosion) since I've had this issue with the voltage I took it all apart and cleaned the connections as another prevention. I did notice that one of my battery cables was loose which led me to believe my battery was bad due to not charging properly or a bad ground as it was the black cable to the driver side battery. As well as the red cable to the passenger side battery had a ton of corrosion on the battery cable terminal and the terminal connector was cracked. I have replaced the battery terminal connectors on all the cables.

I get occasional CEL's from fuel delivery, ECM/PCM voltage intermittent (when that code would trip it would cause the truck to stall/skip for a second and then run normally right after), the brake and abs lights keep coming on and stay on until I shut off the truck for more than 5-10 min. I've already checked my fuses which I'm about to do again as I'm going to be replacing the break cable and rear abs sensor tomorrow as the break cable gets stuck when I use it in the cold as it got caught between the spring and the frame while I was hauling a heavy load and squished the housing so it binds... replacing the sensor since I'm going to be under there and who know when it was done last if ever.

Then next thing to think of is to replace the battery cables all together (I read that sometimes the cables get corrosion under the casing and have poor connection which could be causing my issue).

Any ideas on what I could check or what I might be missing.

Thanks.

 

[Big Lar]

The voltage gauge going up and down is usually when the outside temperature is under around 61f. That is normal as the Grid heater is on.
All your battery connections and grounds need to be just about perfect on these trucks, good clean power is needed at all times.
The crossover cable is always suspect if it hasn't been changed from original, a quick test is to put a meter on each battery independently and if there is a voltage variation of over. 02v more than likely the cable will need to be replaced. Both batteries should be 12.5 to 12.6v as well, if not it's a good idea to have them load tested out of the truck or with cables off both. Hope this helps.
Larry

 

[gavetgp84]

I'll check into that when we did the battery check at advanced auto one was connected to cables and one wasn't and I think they just checked the levels idk if they actually load tested them... thanks.

 

[gavetgp84]

Well, I have changed out all my battery cables including all my ground wired except the big red one going to the starter as I couldn't get to it without removing the starter. My interior lights seem to be brighter (could just be me) ill let yall know how it goes.