Grid Heater Relay Code

[mberry]

Well everyone I have a story to tell here. A short time after I got my truck I installed a TST PMCR. While doing that, I disconnected the batteries like the instructions said. I made sure they were tight after re-installing them Now almost a year later I was getting the grid heater code and CEL. It has been rather cold here lately and I figured it had to do with the draw of the grid heaters and slightly weak batteries. Boy was I wrong!



Now let me tell you I take full responsibility for this. I have not even opened the hood in several months. Last time was late May/ early June of this year when I changed the fuel and air filter.



Today we were heading up the mountain to take my daughter up to play in the snow. For the past few days there had been a strong smell of diesel, so while the truck was idling while waiting for my girls, I opened the hood to check for fuel leaks. I didn't see any leaks of any kind. I even noticed that the engine didn't sounds "right" and I can't quantify that here. What I did find was that the passenger side positive battery cable had worked itself completely loose and was resting on the top of the battery post.



It had burn marks on it from arcing while apparently starting and everything else that draws power. It had been off for a while because the battery post was dirty. Long story longer, I shut the motor off and got my tools out to reconnect the battery. Yes I cleaned the post and cable. I also made sure to check all of the other battery cable connections while I was at it.



I immediately noticed that the engine ran smoother and quieter. I also noticed that the alternator was putting out more than normal, probably due to the one battery not charging correctly.



So I really screwed up and my point of all of this is that if it's been a while since you have checked the cables, you may want to.

 

[Grey Wolf]

You should look under once a week, even if it's just to admire the great engine that's sitting in there

 

[Buddy's Ram]

I had the grid heater low code come up om my truck about two months ago.

Truck ran fine other than the code. I traced the grid heater cables back around the front of the engine to the passenger side fender well. Under the air intake hose are two solenoids that cycle on and off for the grid heaters. The cables were very loose on these solenoids. Took about two rounds to snug them up.

Code gone, lesson learned to keep a check under the hood.

 

[mberry]

...

Code gone, lesson learned to keep a check under the hood.

I agree! I definitely learned my lesson.