I have a 2003 Dodge 2500HD with the cummins diesel. I noticed last winter it was getting more difficult to crank in cold temps so I began researching the problem. I noticed the voltage was not discharging as much as my 2008 Dodge when the grid heater indicater on the dash was on. I checked the voltage to the grid heater relays, all good so I assumed the grid heater was the culprit. After a few hours work and $175 investment, my problem still remains. Everything seems to work fine, when the ambient temp is below 60 degrees the grid heater cycles on, at least according to the instruments, but the voltage still does not discharge but just a little. The indicator goes out as it should and the voltage moves up slightly but the truck will not crank unless I have left the block heater plugged in all night? Any ideas.......??????

JD

 

/Could be a lot of things, but check the easy stuff first. Batteries charged and holding a charge? Ground wires clean and tight? Fuses and relays good? IIRC, the grid heater is controlled via ECM on 03 and up trucks, so worst case is you've got a glitch in your programming that isn't sending full juice. I don't think that's likely, and your biggest culprit is probably a bad relay or corroded wiring.

 

I will follow your advice, batteries are brand new and strong, maybe a bad ground or connection is the culprit.

THANKS!

 

i have found that the connections on the relays are not the best, on mine i crimped them with a pair of pliers to tighten them up, after that no more problems

 

The grids themselves rarely fail, in fact I've never heard of one failing.
90% of the time the problem is the relays, rest of the time it's the intake temp sensor, connections or the fusible link at the battery.
Everything you ever wanted to know about grids> http://dodgeram.org/tech/dsl/trouble...niford_htr.htm

 

Thanks for all the valuable info, looks like I need to get started improving some connections and grounds! Thanks for the great tips!

JD

 

Probably just weak batteries and bad connections.