OK to replace GP's first, then wait to see if module is needed?

sprinterpirate

not an electrician.
Hi folks,

I first read through a number of glow plug threads, and haven't yet seen a clear answer on a couple questions--probably because it is obvious to everyone but myself! :thinking:

Some of the threads I checked:
https://sprinter-source.com/forums/showthread.php?t=27223
https://sprinter-source.com/forums/showthread.php?t=18156
https://sprinter-source.com/forums/showthread.php?t=24060
https://sprinter-source.com/forums/showthread.php?t=12150
https://sprinter-source.com/forums/showthread.php?t=6935

I have a number of glow plug faults on my 2004 T1N with just under 100k miles. I'm thinking of following this sequence:

  1. Spray PB Blaster on glow plugs today, then wait a week for parts to show up
  2. Warm up the engine with a drive, then let it cool for 15 minutes
  3. Back each GP out a quarter turn, taking care not to use too much torque
  4. Spray threads and let soak another 20 min
  5. Remove GP's
  6. Install these plugs: http://www.dieselrxproducts.com/glow-plugs.php http://www.summitracing.com/parts/drx-drx00024
  7. Use dialectric grease on the connector clips
  8. Drive it around and see if the check engine light goes out. If it does not, consider replacing the glow plug relay module with this: http://www.ebay.com/itm/For-DODGE-F...2AA-/151306950524?hash=item233a98d77c&vxp=mtr [it appears to have a different part number than the one mentioned here often, but I'm pretty sure its the newest version]

My questions:
  • Do I REALLY need to ream out the threads, seats, etc? I'm hoping to avoid this, assuming the plugs don't come with terrible deposits... I have seen mixed opinions about this.
  • Do I risk causing damage to the new glow plugs if my GP relay module is already busted?

Thanks!

:popcorn:
 

surlyoldbill

Well-known member
If you have the old style module, it's probably toast. The new style module has self re-setting breakers, and won't be toast. The difference? I don't know the part numbers, but the new style is thinner front to back. Look up some pics on the web.

No damage to new plugs if the module is toast, because it won't be sending any current.

I'd at least clean out the threads with a solvent soaked rag if you don't want to clean them with a tap. Remember to use an air gun to blow out gunk from cylinder before putting in new ones.
 
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sprinterpirate

not an electrician.
If you have the old style module, it's probably toast. The new style module has self re-setting breakers, and won't be toast. The difference? I don't know the part numbers, but the new style is thinner front to back. Look up some pics on the web.
Aha, thanks Surlyoldbill! I'm inferring that its more likely my glow plug faults are related to a bad module than a bad GP--or that a bad GP is most likely to result from a bad module. Either way, I suppose I should just go for it and dissect the existing module. Perhaps I can pull off some minimally invasive diagnostic surgery.

Pretty sure I have the old relay module.... Based on this discussion [ ] I originally had the following understanding:
  • 000 545 36 16 = old version with fusea
  • A 648 900 00 00 Q 01 = new replacement module

But the part number on my module is 028 545 4032.... looks like djc126 already has modded one of these, so it must be one with fuses. Perhaps 028 545 4032 was an intermediary part between the original and the most recent version?

OK, I'm going to do some "empirical research". I saw you mention that you're steering people to the new module with the breaker, rather than sell your modded module... But I do like the idea of being able to diagnose GP problems quickly with your fused setup. You still making those?

Will def. blow out the gunk and clean the threads as you suggested! Thanks again.
 

sprinterpirate

not an electrician.
Well, it definitely is burned out:


Incidentally, i peeled off the sealant between the plastic shell and the side (with plugs) that the circuit board is connected to. The shell has four tabs (one on each side) that can be pried away using a butter knife. Thought i would mention because in the pictures I have seen, the plastic shell was cut apart...
 

sprinterpirate

not an electrician.
Also I am sad to say I managed to shear off the threaded post welded to the firewall while attempting to remove the nut. Strange, because the nut on the other side of the relay module had no corrosion!
 

surlyoldbill

Well-known member
Yep, that's an old module. You can mod it with about $30-40 worth of parts. I stopped making them because they became obsolete.

I wondered about making a stealth mod; soldering ATM fuse holders on the module itself. This would eliminate the problematic main power source soldering of the 10g wire, and you don't need to buy wire or a fuse block. I'd solder each end of the ATM holder spanning the burned (or cut) link.
 

sprinterpirate

not an electrician.
I wondered about making a stealth mod; soldering ATM fuse holders on the module itself. This would eliminate the problematic main power source soldering of the 10g wire, and you don't need to buy wire or a fuse block. I'd solder each end of the ATM holder spanning the burned (or cut) link.
Wow cool!

Like a few of these?
:bow:
 

baja

2004 2500 Leisure 210B
PB Blaster used to be my favorite penetrating oil, a 50 / 50 mixture of acetone /ATF works much better. Try it you'll like it, but you must shake it before you use it. Baja
 

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