Glow plugs not shutting off when ignition is off

My glow plugs are not shutting off when I turn off the motor and remove the ignition key from my 2004 t1n. I discovered this when my battery was dead on more than one occasion in the morning. I had new glow plugs installed this summer, but they had not replaced the glow plug module, so I ordered one and installed it about 2 weeks ago. The problem has not gone away.

I have found that after I turn off the ignition I can turn it back on partway (until the glow plug indicator lights up on the dash) and then turn it back off and remove it and the glow plugs stay off as they should. However, I'd like it to work correctly.

Have any of you heard of this? Thanks for any ideas.

Following this. I'm tired of changing batteries. In my case, on a stop and go delivery day my battery slowly discharged until I had to switch it, I unplugged the glowplug relay and problem went away for weeks. Unfortunately it's below freezing now...

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Ok here I saw a simple Old school solution. Install an indicator light on dash so,you know when the GPs are hot. Also if they stay on when driving they will fail soon, so you need to know. You could also put a high amp relay inline to the GP module relay and override it as required.
Or....you could work out exactly what is wrong (the correct path) but sometimes there isn’t the time or money to chase down problems.
I’m guessing the key switch may be the culprit.
My last diesel van the gp module and associated wiring was a constant problem due to poor design.
In the end I just built my own relay and wiring harness, by passing the OEM stuff, no more
problems.
To be fair the MB system is more robust (once the fuse based module was replaced) so a simpler solution may present itself.

How do you know its the GPs? Are you seeing current/voltage at the plug terminals?

Its possible the ECM is not going to sleep, if so, you need to check that the ignition switch and ECU/ECM relay are turning off with the key.

Have you had the T21 recall performed?

On a 2004 this can lead to the ignition not turning off fully.

Keith.

Midwestdrifter said:

How do you know its the GPs? Are you seeing current/voltage at the plug terminals?

Its possible the ECM is not going to sleep, if so, you need to check that the ignition switch and ECU/ECM relay are turning off with the key.

Click to expand...

Well, I have 3 batteries. I don't know what else would draw enough current.

As for the recall, I've avoided it like the plague. Emissions have been scrapped in Ontario this year, which helps

I like the suggestions tho.

Referring to the diagram, there's only one wire that commands the GP module to act.
It's pin 2 on connector 1: Black with a Red stripe.
If disconnecting that "cures" the problem, then it could be either harness damage (suspect the bend behind the fuel filter) or an ECM issue.



It's a dinky wire (18 gauge) so it's not carrying much current.
Quick fix would be to add a switch in *that* line..

By a similar token, if the brown Ground wire (pin 1) is broken, it could cause the module to "float" and think it's being asked to be "on". So check Ground point 100 and the wires leading to it.

--dick (diagram from 2006 manual: http://diysprinter.co.uk/reference/2006-VA-SM.pdf )

Cheyenne said:

Have you had the T21 recall performed?

On a 2004 this can lead to the ignition not turning off fully.

Keith.

Click to expand...

I have had the recall performed. It didn't lead to any immediate issues. This seemed to begin a few weeks after having the new glow plugs put in. Maybe the recall is the cause?

I have a 2011 2500 sprinter looking for the fuse box for glow plugs

Wallydport said:

I have a 2011 2500 sprinter looking for the fuse box for glow plugs

Click to expand...

Wallydport,

Your 2011 is an NCV3 and not a T1N so you would be better posting your question as a new thread in the NCV3 Talk sub forum.

Keith.

Decided to get a cheap battery monitor, keep an eye on draw/charge. I like Patrick of M's idea of the "glowplugs active" light too

Should be useful to see how the alternator is doing too, without having to plug in the scanner while driving...

Issue is so infrequent, happens maybe twice a year


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