Glow plug light. - PeachParts Mercedes-Benz Forum

brownrice78 · #1 02-24-2009, 10:15 AM

Quick question. If one of the glow plugs is not working, would the glow plug light still work properly??

brownrice78 · #2 02-24-2009, 10:17 AM

Ok..nevermind...I thought about it a bit and realized that the light would still work properly as long as power to going to the plugs. Whether or not they actually heat up is a different question..am I right??

milner351 · #3 02-24-2009, 01:00 PM

this is one of those times I'd really like to have a non contact thermometer - I'd think you could "point and shoot" at each GP connection and see a dramatic temperature difference if one is not heating at all.

JonL · #4 02-24-2009, 01:23 PM

It's my understanding that the relay is able to detect an open circuit on one or more glow plugs and keep the indicator lamp from lighting when there is such a defect. That seems to be how mine functions, although I now have five good glow plugs and about half the time my light doesn't come on, even though the relay is obviously energizing the glow plugs. I think I have a fault in the relay itself, which is on my list to look at.

babymog · #5 02-24-2009, 01:35 PM

On the 602/603:
A bad #1 GP will cause the GP light to not come on.
Any two of GP #2-#5 (or #2-#6 on the 6cyl) will cause the GP light to not come on.

I don't know about other engine models.

toomany MBZ · #6 02-24-2009, 07:58 PM

On my SD, only one plug had failed, the dash light acted up.