I am having a major issue with the electrical system at startup. I turn the key to run and voltage meter goes up to around 9, then sluggish start. After a couple mins, voltage meter comes up to 14+. No problems with running just startup. I have replaced the alternator, one battery, and one battery cable. I have tested all that I can think of. Placed it on a charger at 40 amps and when I turned on key, voltage meter jumped up to about 16+. I need help, at a loss now. Have no clue!!!

 

Sounds like the grid heater cycling at start. Its normal for the voltage to drop to ~9 at first start and then raise and drop 9-14 after start and lights dim if the temperature is below 60 degrees. What is the outside temperature when you are starting?

 

I don't think it is the grid heater because it doesn't matter the temp outside. One day it was eighty and I had just drivin about seventy miles so the engine was already warm.

 

Do you have any aftermarket electrical accessories installed in your truck like extra lights or such? The only other things i can think of in the charging system is the TIPM and the battery temperature sensor.

 

ALWAYS REPLACE BATTERIES IN PAIRS. Never change just 1 battery. Go replace that other battery with an identical one to the one you replaced. You may have already ruined your new battery.

 

Both batteries have been replaced and still having the same issue. No extras added like lights or anything.

 

Additional info, have now cleaned all connections, replaced both batteries, one cable (no corrosion on any others, when I turn key on there is a steady clicking from inside the valve cover. Have checked and cleaned all connections to air intake heater and clicking does not appear to be coming from there. Please help. Getting frustrated.