jbritvar

So I have been having this problem since I had my motor re-built. Basically, when I am riding down a hill or even a minor decent (not accelerating) the grid heater light comes on the dash, beeps god knows how many times and then stays on until I clear the code. Additionally, no code is known for this issue. One mech said it was my grid heater solenoid and I have no idea what else it could be. If anyone gots some ideas please let me know.

Thanks yall

jbritvar

I should also mention that I had been having some issues with electrical connections such as oxidation and what not. I recently replaced the 12v on the primary which was the worst. Since then I have had lot fewer issues. I also need a new cooling fan becuase apparently the speed is off.

rip 112

Corrosion is suspect, but check for codes with the key sequence.

Key on, key off, key on, key off, key on: look in odometer window for codes, if codes are present they will show then display -done-. This will give you a better idea of what the grid heater is showing, whether it be low voltage or whatnot.

jbritvar

Here are a list of codes from my flashpaq. I have not yet read codes from above sequence ^.
PO480
PO483
PO541
P1222
B18BB
B1661
UO184
The top two are for the fan speed, and a couple others are for communication with radio, window voltage? and fog lamp voltage.

I also forgot to mention earlier is that, once this code throws, there is a significant drop in power. I mean significant. Almost as if it is going into limp mode.
Where I am confused is that it ONLY comes on when I am going down grade without accelerating, and if I am to leave it on until it goes off, it goes off at complete random.

carl48

the grid light and beeping is a warning usually associated with a faulty fca. you do not have your sig filled out so a little guessing. I think you have a 5 volt supply wire touching ground. on some year models around 06 it is by the a/c pump bracket, the wire loom did not cover it and rubs a hole in the insulation causing the intermittent problem. a cfm+ horn raises the dipstick tube up high enough to rub the wires

jbritvar

Ok so is there a way for me to test the fca. And correct me if im wrong but its located on the back of the CP3? And im not clear on what you mean by my sig filled out? My truck is an 07 5.9 so I will check for that 5v. Any hints on where that a/c pump is?

carl48

look at my and rip 112 post, at the bottom we have our truck description, this helps us in diagnosing your problem. crawl underneath the passenger side where you can see the alternator and air conditioner compressor, I think it is the bottom rear bracket there is a wiring harness that has a 5 volt control wire in it that did not get the protected loom and has caused many hundred problems like yours. I got hit with two of my trucks. the fca is on the back of the cp3 and your symptoms are not consistent with a fca problem, that is why I think it is a 5 volt supply problem

jbritvar

Ok thank you so much. I will keep yall updated on what I find

rip 112

Check what carl48 is saying, and get rid of your corrosion problems, bad connections are more prevalent with corrosion.