Voltage regulator problem?

[mopeg]

Hi there,



I have noticed over the past several months that when I start the truck ('06 5. 9 TD) after a period of non-use that the voltage needle will rise beyond the middle "14" approximately 1/2 way to the upper end of the normal range. Soon there will be an audible click and the needle will fall below the "14" along with the dimming of lights. Soon another click will be heard and the process repeats itself for 3 - 4 repetitions and then the needle settles above the "14" and will stay this way. If the truck is shut off for more than 5 minutes, the whole thing repeats itself. As time has gone by the swing below the "14" is getting deeper almost to the lower level of the range. So does this mean the voltage regulator, which I understand is part of the alternator, is going out?

 

[B.G. Smith]

Is it cold where you are located. The intake air heaters energise at temperatures below 60 deg. f and cycle until the engine warms up or you reach a certain mph when driving. Don't know about the voltage geting lower unless your batteries are getting weak or need charging. I believe the voltage regulator is in the PCM on thes trucks. bg

 

[mopeg]

I live in Western Washington where the temp this time of year is usually above freezing. The batteries are 2 yrs old. What is the PCM? The volt meter registers above 14 consistently after a few minutes of driving and remains there even when down to an idle.

 

[JFaughn]

PCM = Power Control Module , the computer that runs & monitors most everything .
What you are seeing may be normal , cycling grid heaters , you can check with shop / dealer to double check .

 

[KarlC]

I'd say the voltage gradually getting lower is 'cuz your batteries are getting older. The intake heaters draw more than the alternator can put out, so for the time when they're on it's running on battery. This shouldn't be a problem so long as they still start the truck on the coldest morning. If you plug in the block heater for a couple hours before you start it, the intake heaters will run for a shorter time.

 

[mberry]

What you are seeing is perfectly normal this time of year. The colder it gets, the lower the voltage will read because the grid heaters are drawing more amps from a colder battery. No problems.