ECU light after heater plugs done

Hi again. The only problem I have with my 2000 sprinter cdi I'm collecting is after having the heater plugs changed last week, the engine management light has come on. The van still drives well so I'm guessing a wire was dislodged while the work was being done.
Any ideas?
Cheers

Which light exactly is it?

If it is the Malfunction Indicator Light (MIL), or sometimes called the "Check Engine" light, that is on you really need to connect a code reader and find out what trouble codes are stored. To do anything before reading the codes is just guessing. It may not be related to glow plugs at all.

Back to glow plugs, you said the glow plugs were changed. Was the glow plug control module also tested or changed out? I did a search. Doktor A outlines some test procedures here:

https://sprinter-source.com/forums/showthread.php?t=743&highlight=glow+plug+test
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A quote from Post #8
Originally Posted by acvr4 View Post
I seem to have just started to have a problem with my #4 Glow plug & module -- that's the codes that pop up- have to love these Scan guages . It doesn't happen all the time just every once in while. I'm getting a set of new ones to change them but could there be a loose connection ? I'll be checking it either tonight or tomorrow but just checking for some heads up before hand.

"The DTCs set by the glow plug module(also referred to as glow plug relay) are unreliable. An indication for a particular cylinders glow plug failure may involve a completely different cylinders glow plug OR non at all-it typically indicates a defective module. DC has FINALLY acknowledged this DTC problem in the latest release notes for the DRBIII sprinter memory card update. The module(relay) part# was 5103568AA and has superseded to 5170859AA-about $110.00 from Dodge. BTW, a defective glow plug can damage a new replacement module-so don't replace a specific single glow plug based on DTC info-then find the problem is still present -then replace the module only to have the undiagnosed defective glow plug destroy your new module." Doktor A
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You might also be interested in Post #18.

Hope this does some good. vic

The statement above regarding the unreliability of DTC is quite accurate - I'm in the middle of changing out a bad glowplug that was shorted to ground. My code reader had been reporting it as the glow plug in cylinder no. 4 - upon testing, as per Doktor A's fuse method, I discovered the bad glow plug to be in the middle cylinder, which I assume is cylinder no. 3.

Now ..... to get that little bigger out of there in one piece, without snapping it off .....

Hi. I think it says EDC or something similar. Picking it up tomorrow. It drives and revs great so it isn't limiting like some vehicles do.

don't know if this helps or not but it says in the manual that one of the reasons that this light comes on is because of a dirty fuel filter that might need replacing.

Well it just got worse. I've only driven the thing 30 miles and now the glow plug light goes out then comes back on and stays on. I guess I need to get a diagnostic meter on it. Think I just been ripped off although guy did seem genuine and a friend of a friend. Maybe I'm just unlucky as I have had it confirmed by A.N.Other that the heater plugs were replaced last week.
AAAAAAAAAAAAAAAARRRRRRRRRRRRRRHHHHHHHHHHHHHHHHH!

So, it appears that the previous fault still exists. Bad luck fella. There isn't much to the glow plug circuit, so a check of glow plugs, glow plug relay and associated connections via a diagnostic plug in will quickly establish whereabouts amongst these parts the fault lies. One wonders if all the glow plugs have really been replaced, or if a stubborn and faulty original one remains, possibly also taking out the relay?

I actually managed to get hold of the chap who fitted them. He had to drill and helicoil the back one in full view of the last owner so I know they were done (the owner was a friend of friend and was quite a genuine chap). Have just had a mechanic have a quick look but he couldn't remember where the diagnostic plug is (didn't have his machine with him anyway) so if anyone knows where it would be on a 2000 208CDI...................

Passenger footwell, under the glovebox and to the left.

Thanks

Well I've found the plug, just need the man with the machine to find time to plug it in. I've found the big control module under the dash but still can't find the glowplug relay.
Is it ok just to unplug and plug the leads looking for a dodgy connection is is it a no no?
I have bought a Mercedes Wiz program and loaded it on the PC but think I need to pass the Space Shuttle programming course before I move up to the Wiz program, so any recommended workshop manuals or just the standard Mercedes one?
Still learning (fast)