Except he hasn't thrown a CEL...I guess it is possible there is a stored code but it really isn't too crucial to know which it is until the IM comes off, then he can just test them at the plugs themselves. I suppose if he wanted to do a favor to the board he could "map" the glow plugs by checking each wire and noting which pin on the relay plug corresponded to that wire while he has the IM off but knowing which plug is bad isn't really important until he's ready to replace it and still you'd want to confirm by testing at the glow plug before you start to remove it.

__________________
Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

Well now, this begs that age old question: replace the bad one or all six?

__________________

Muleears
'07 E320 Bluetec 133K my DD
'04 Jaguar XJ8 VDP, 34K
'10 Hyundai Accent 60K Grocery Getter
'02 VW Golf soon to be on the road again
'97 E300 Diesel Son's DD
'61 VERY tolerant wife

Hampton Roads, VA USA

Gone but not forgotten:
'67 250S 95K
'86 300SDL
'87 300D Turbo, 364K! R.I.P.
'98 E300 Turbodiesel, 213K
'02 S420, 164K
'01 Prius 138K

Do you feel lucky, punk?

Seriously...you will hear rational arguments on both sides of this...my position is change the one which is bad, use an O-E M-B plug and wait for the next one to blow. It's just not worth the risk of breaking one off to perform a complete change of all plugs as preventative maintenance.

Now, if you are unlucky enough to have the bad one break off, and have to remove the head anyway then go ahead and do all 6.

The GP's cost about $35 each. Generally, like light bulbs they willl work until they quit but there is no telling when one will go out. Fortunately losing one won't leave you stranded and it takes less than an hour to R&R the IM and replace one if you are experienced at it.

__________________
Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

I tend to agree. I would be glad to map which contact goes to which plug but how would I go about it? Put one lead on the plug and one on the contact and see when I get .6 ohm?

__________________

Muleears
'07 E320 Bluetec 133K my DD
'04 Jaguar XJ8 VDP, 34K
'10 Hyundai Accent 60K Grocery Getter
'02 VW Golf soon to be on the road again
'97 E300 Diesel Son's DD
'61 VERY tolerant wife

Hampton Roads, VA USA

Gone but not forgotten:
'67 250S 95K
'86 300SDL
'87 300D Turbo, 364K! R.I.P.
'98 E300 Turbodiesel, 213K
'02 S420, 164K
'01 Prius 138K

Once you have the IM off and disconnect the wires to each GP it would be a 5 minute job. Just put one side of the ohm meter on the wire to a GP and probe the relay plug until your meter shows a short-circuit, then label it and do the next wire.

__________________
Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz