Codes PO380 & PO671

Hi all, I'm looking for some help. I have a 06 2500 with 97,000. Other than my turbo resonator failing at 1,300mls (now I have the aluminum replacement), it's been a great truck. The engine light came on back in May, day after my 90,000 oil change at the dealer. I bought it back to the Dodge dealer and they informed me it was the Glow Plug(s). Don't remember if he said plug or plugs, but told me don't worry, it's warm now and no need to replace it right now. The light came on intermittently over the summer, but no issues at all.
I brought it to my independent mechanic that services my Astro/Safari vans, He replaced glow plug #1 yesterday. This morning the engine light came on again, brought it to him and he got the same code, PO380 & PO671. Could it be the Glow plug controller? Any thoughts? Thank you in advance.

P0380=Glow plug heater circuit A
P0671=Cylinder 1 Glow Plug Circuit / Open

I suspect you have a duff controller, these units were modified recently to a slimmer module made in Germany. Much improved and more durable!

You might also have a suspect harness so its worth Ohming it out and look for shorting/ damage etc.
Make sure the system is fully cleared of faults.

Some scanners demand that you turn off the ignition for 10 seconds after clearing to wipe the memory.

If you have a scanner which has mode 6 on it, go through the cold start circuit and fire it up.
If you have fixed it the mode 6 and the pending will show no faults on some scan tools.

I hope you are using a genuine MB glow--NO Chinese stuff--unless you want to invite trouble!
Dennis

Keep in mind that if you Sprinter tells you Glow Plug (GP) #1 is bad, it actually could be any of the glows plugs. The wiring harness is such that any GP wire can plug into any of the 5 GP's and they often are connected out of order.

If your GP opened up (rather than shorted), then just changing the GP should fix it (provided you got the correct one), however if it shorted out, then it blew a fusable link in the GP controller. If you have not modified your GP controller (discussed on this forum) to have replaceable fuses, you will always get an error from the GP controller (as Mercedes made them to be replaced when that occurred).

The GP controller is under your starter battery.

It's likely that the wrong GP was changed and/or you have a blown fusable link in your GP controller (These are pretty expensive to replace). I would look into adding the external fuses to the one you have.

Here's the thread you need to read about modifying your glow plug module to eliminate the fuse issue. It's a couple of hours worth of work if you are relatively familiar with electrical wiring.
https://sprinter-source.com/forums/showthread.php?t=12150&highlight=Glow