2nd Gen Non-Engine/Transmission 1999 2500 4WD Charging System

[REdmon]

I noticed the headlights on the truck were normal output and then I could hear a click (some type of load being applied) and the headlights dimming a little bit. After a few seconds, another clicking noise and the headlights would go back to normal. After a few days, the truck wouldn't start. The batteries were 6 years old so I replaced them both. A few days later and the truck wouldn't start again. I just finished replacing the alternator, but I still see a load being applied as the voltage cycles between 13-14. 5 volts. The "check gages: light goes out after starting but I wonder if I have a bad PCM or some other module. Any suggestions are appriciated. Thanks, Ron

 

[JFought]

Grid heaters sticking?

Placerville CA? i used to live close to their. . then moved the hell outaa CA!!

 

[JFought]

fill out your info>> yr model mods, ect

 

[REdmon]

The year and model are in the subject line. 1999 2500 3/4 ton 4 wd.

 

[KRStone]

edited ... ...

 

[WilsonF]

Before running out and getting a new alt. take it to a place to have it tested. If bad, and if it is the OEM, don't use it for a core, have it rebuilt. I tested my Voltage reg. in the PCM by adding an external voltage reg. This is one way of doing it.

Alternator external regulator how to 89-02 - Dodge Cummins Diesel Forum

The cycling is most likely the grid heaters.

Floyd

 

[REdmon]

If the cycling is most likely the grid heaters (have to see what those are), how do you remedy that situation? Sorry, not to knowledgeable with all the systems.



Thanks,



Ron

 

[Joe Mc]

Grid Heaters = a set of electric resistance heater (grid) between the intake horn and the intake (left/driver) that provides a warm air charge when you turn the key to fire. As with some other diesels still use "glow plugs" (in the combustion chamber) to provide warm/hot air to aide start.

When you turn the key on and "wait to start" comes on, the grid heaters cycle on, then off after "wait to start" goes off. After you start the engine the "wait to start" obviously will no longer light, however, the grid heaters still "may" cycle on/off based on outside air temperature and vehicle speed - bla, bla, bla. In essence you can be driving under 15 mph and see the gage cycle from 14 to 10 or lower and the lights dim. If once you get going over 15 mph (pretty sure its 15? could be 20) the grids should no longer cycle. Additionally, once the coolant reaches operating range - temp gage starts to move away from 140 and up - you should no longer see the volt gage fluctuate if you do then there's something else going on.

Good luck - hope this helps some. It is not uncommon for the head lamps to dim and brighten in unison with the grid heaters cycling.

 

[JFought]

yes, lights dim when grid heaters come on/ a side effect of amperage draw, hence they cycle on and off due to the amount of power it draws.
the dimming headlights match the voltage gauge drop when the grids are on/cycling.