Good suggestion.

I checked the glow plug relay. It operates as expected and the relay seems fine. The relay has a constant 12-V (big wire) supply and all six contacts that go to the six glow plugs get 12-volts anytime the relay is engaged. The relay must be engaged from voltage supplied by a smaller wire.

The problem is that I don't always get the voltage (small wire) required to engage the relay. I need to determine why I sometimes don't get this voltage when I turn the key.

Could this be only a problem at the ignition switch or could it be something else (the computer or something)?

__________________
Neil
1997 E300D - naturally aspirated
280,000 miles (as of November 2015)

It's either the ignition switch directly, or a relay. A wiring diagram is needed.

Best Regards,
Jim

Another likely culprit is the glow-plug strip fuse. It is notorious for developing hairline cracks, and/or making intermittent contact with its mounting screws. Change fuse and try again.

Phil

__________________
'95 E300 Diesel, 264,000 Miles. [Sold it]

Jim: I agree - I would love to have a wiring diagram but so far I can not locate one. I apologize if the post on the diesel discussion board was also mine that you responded to. I'm not sure if it was. I posted my question in the "Tech Help" AND the "Diesel Discussion". Please let me know if that's taboo and I will not do this again. I was obviously looking for maximum exposure. Thank you for your insight on my glow plug problem.

Phil: Where is this fuse that you speak of? What amperage rating is this fuse? I have seen no fuse. Thank you also for your input.

If I don't respond for the next few days it's because I just found out I live in a mandatory evacuation area for Hurricane Dennis. Tomorrow will be busy boarding up the house and who knows when I'll get back to the computer or have electricity.

Thanks again guys.

__________________
Neil
1997 E300D - naturally aspirated
280,000 miles (as of November 2015)

FYI: I closed the thread on the diesel discussion board to eliminate confusion and duplicated efforts.

__________________
Neil
1997 E300D - naturally aspirated
280,000 miles (as of November 2015)

Please accept my appolgy, it was rude of me to yell. (I have removed my rude remarks.)

I do not think that the 80A strip fuse will be a culprit in this case, since you state that the relay sometimes activates, and other times does not. The fuse is a flat strip of metal bridging two phillips screws on top of the relay.



A melted fuse strip does not affect the relay; the coil still energizes and the contacts close, but cannot apply 12V to the GPs since the strip is open.

It may be the ignition switch contact, it may be a connector.

I hope somebody here has a wiring schematic and can help further.

Best Regards,
Jim

My appologies for yelling. Double-posting is not taboo, and will get maximum exposure, but it can also be counter-productive, like trying to listen to two simultaneous conversations.

You said that your relay is not receiving power at times. That said, I don't think it will be your fuse strip, since if the fuse melts the relay will still continue to function, the coil will energize and the contacts will close, there just will be no 12V applied to the GPs since the fuse is open.

Sorry, I don't have a wiring diagram for that series automobile.

Best Regards,
Jim

FYI: Did you know that you can delete threads started by you, Click the check box then the delete button.
I deleted the thread I started in Diesel Discussion, here are the posts.
Thank you Wes and P E H.

whunter
Senior Member Join Date: Dec 2003
Location: Metro Detroit, Michigan
Posts: 3,002

To answer your question:
The most likely cause of your problem is a bad key switch or failing glow plug relay.
You can open the glow plug relay and check the contactor points, if they are badly burnt, it may be possible to clean them with a file.

whunter

#3 Today, 12:04 PM
Wes Bender
Retired User Join Date: Mar 2001
Location: Alpine, AZ / Green Valley, AZ
Posts: 466

I think he closed it intentionally. He left the same thread open on the Tech forum...

(but your advice is right on)

Wes

Wes Bender

#4 Today, 12:29 PM
P.E.Haiges
Registered User Join Date: Jan 2000
Location: PA
Posts: 3,930

There is a timer in the GP relay that keeps the GP energized for about 45 seconds. Possibly that circuit is not working properly and not keeping the GP turned on.

P E H

Thanks for the replies. Hurricane Dennis has not allowed me to work on my problem. I'll review the posts (and my car) more closely this weekend and report back.

__________________
Neil
1997 E300D - naturally aspirated
280,000 miles (as of November 2015)