I moved this thread from 2nd gen to here because it has more to do with diesels than not.
So I have a 2000 Ram 2500 4WD, I am getting a P0382 code, first I checked if all the wires were plugged in and they were. Then I replaced the solenoid set, rechecked the wires cleared the code and it instantly shows the code again. Next I checked the grounds on the small terminals they checked good going to ground also. I also removed the two small terminal grounds and made a new wire set to directly ground them, cleared the codes and the P0382 again instantly re-appears. So I guess it can be one of two things, either the plus side of the small terminals have a break or short in them or the ECU is malfunctioning.
I could really use some advice.
TIA

 

The P0382 is talking about grid heater relay failure...... Verify your are getting power TO the relay, on the control side of the circuit.

 

Correct me if I'm wrong but shouldn't there only be power at that small lug (plus side wire) during starting and when the temperature is less than 40 F?

 

Looks like you are correct. PCM supplies power to the control side of the circuit to activate the relays.

However... It looks like the power side of the relay for the grid heaters is hot at all times. Powered pretty much directly off the battery, via a fusible link. (I think that would be pin 30 on the relay socket.) Got power there?

 

The power side of the relays have power, I checked before and after the fusable links it's good and I have 12V at the solenoids. You did lose me on the pin 30 of the relay socket, we are talking about the two "Ford looking starter solenoids" right?

What's also odd to me is that I can clear the codes with either of the two readers I have and in both situations the check engine light and the P0382 come back in one second after clearing it. So I wonder if the power to the relay is either open or shorted right to ground or the ECM is malfunctioning. I'm guessing the ECM must be doing an ohm check as soon as the key is turned on regardless of need to turn the heaters on.

Thanks

 

From what I see on internet schematics there is one control power wire from the harness and two returning wires which lets the ECM know which solenoid / relay is malfunctioning. The P0382 I believe is solenoid / relay 1 (although I don't know which is which). I guess I could put an ohm meter on both wires and see if I get a different reading from the two wires.

It would be easier to remove my own spleen by my self.

 

Finding another schematic:
https://mopar1973man.com/cummins/art...ing-maps-r469/
I think I narrowed it down to the schematic "Engine Systems page 3".
The yel/blk wire at terminal 29 of the ECM module to terminal 2 of Intake Air Heater relay No. 1.

Or who knows????

 

To the best of my ability I checked the continuity between the socket at terminal 29 and power side of relay No.1 and there is continuity.

So anyone have any eye of newt or toe of frog I can sprinkle on it??

 

Check wiring diagrams here. They seem to be pretty accurate.

Ok, so the relays are actually large solenoids. I didn't know that. Have someone else turn the key on, while you are checking for power at the relays. (solenoids) See if power goes away on one of them. The wire might be good enough to show voltage, but, put a load on it, and it's gone.

 

So I checked the heavy 12 v terminals and the solenoid closest to the cab, had my wife turn the key and it does pull, the other closest to the bumper does not. I then check continuity between socket 47 and power terminal on that solenoid and what do you know there is no continuity.

So looks like I have to tear open the wiring harness and look for the open.

Thanks, you have been lots of help.