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  #1  
Old 04-16-2012, 04:54 PM
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Inside the box: VDO Glow Plug Relay 5 Zyl

Hey everyone,

Forum member yuke was kind enough to send me a his old glow plug relay to see if I could figure out why it was sticking on after he shut his car off.

PN: 001 545 98 32, from 04/1985

Here's some pictures of the unit:






It looks like something happened at the contacts. It looks like the unit can be salvaged but I'm not sure on how to repair the bad contact pad on the relay...





Credit goes to scottmcphee for this modification, originally performed on a 6-cyl glow plug relay:

I didnt have a 56 ohm resistor so I put a 22 and 33 together. It works out better because I now have a 1-watt resistor. I decided to install it on top of the PCB as there was little room to nicely install two resistors on the bottom. If you just got one resistor you could probably do it on the bottom just fine.






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  #2  
Old 04-17-2012, 02:17 AM
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Clean the contact and try silver soldering it. If it looks like that isnt going to do it, there is always JB weld or Devcon.
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  #3  
Old 04-17-2012, 03:41 AM
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Hey James,
With a little luck there will still be a bit of hard metal left on the relay contacts. In years gone by we used to clean/dress ignition points with a points file. Havent seen one for years. The cheap alternative for you would be to fold over a strip of 120 wet&dry paper & use it as a double sided file. A little water on it helps. If you do it with the contacts in place ~ assembled relay, you will have good contact, that is parallel faces, when you smooth the bumps off.
Good Luck !!
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1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
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1968 Ford F750 truck. 6-354 diesel conversion.
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  #4  
Old 04-17-2012, 03:51 AM
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Quote:
Originally Posted by layback40 View Post
Hey James,
With a little luck there will still be a bit of hard metal left on the relay contacts. In years gone by we used to clean/dress ignition points with a points file. Havent seen one for years. The cheap alternative for you would be to fold over a strip of 120 wet&dry paper & use it as a double sided file. A little water on it helps. If you do it with the contacts in place ~ assembled relay, you will have good contact, that is parallel faces, when you smooth the bumps off.
Good Luck !!
Good idea! I'll have to see if I have any 120 grit sand paper. I had some 600 laying around so I started off with that.

I put the relay in my one 300SD it seems to work fine. The light mod seems to work as well.

Other than the contacts being beat up, I didnt see anything else wrong with the unit.
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(4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!)


82 300SD 145k
89 420SEL 210k
89 560SEL 118k
90 300SE 262k RIP 5/25/2010
90 560SEL 154k
91 300D 2.5 Turbo. 241k
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  #5  
Old 04-17-2012, 08:34 AM
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Quote:
Originally Posted by JamesDean View Post
I had some 600 laying around so I started off with that.
600 will take for ever !!!
If you can borrow a emery nail file board, it may work. you know, the type girls use & throw away when their done.
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I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving
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  #6  
Old 04-17-2012, 01:15 PM
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Quote:
Originally Posted by layback40 View Post
Hey James,
With a little luck there will still be a bit of hard metal left on the relay contacts. In years gone by we used to clean/dress ignition points with a points file. Havent seen one for years. The cheap alternative for you would be to fold over a strip of 120 wet&dry paper & use it as a double sided file. A little water on it helps. If you do it with the contacts in place ~ assembled relay, you will have good contact, that is parallel faces, when you smooth the bumps off.
Good Luck !!
If you look closely, I believe AutoZoo still sells them. You just have to look hard, and nobody knows what your asking for if you ask them. I still have points files from my aircooled VW stint a few years back
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  #7  
Old 04-17-2012, 02:29 PM
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WOW, that contact took a LOT of heat...
cleaning it up will likely get it working for a short time, but that plate is shot. it'll just keep failing.
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  #8  
Old 04-17-2012, 02:48 PM
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Purpose of the "glow plug lamp modification?"
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  #9  
Old 04-17-2012, 02:55 PM
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The heat may have came from arcing due to poor contact. As the contact got worse It got hotter, which made it worse, which made it hotter... The heat may have goofed up the fit between the contact pad and the part it mates with as well.

What exactly does the light modification do?

Thanks for the pics!
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  #10  
Old 04-17-2012, 03:06 PM
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Quote:
Originally Posted by 1980sd View Post
The heat may have came from arcing due to poor contact. As the contact got worse It got hotter, which made it worse, which made it hotter... The heat may have goofed up the fit between the contact pad and the part it mates with as well.

What exactly does the light modification do?

Thanks for the pics!
It would let you know that the glow plugs are not turning off.
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  #11  
Old 04-17-2012, 03:22 PM
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Yes, the light modification connects the relay's output to the lamp on the dashboard. The lamp will be on at about half power indicating that the glow plugs are running. If the lamp does not turn off when you turn the car off, you'll know the plugs are still powered.
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Cruise Control not working? Send me PM or email (jamesdean59@gmail.com). I might be able to help out.
Check here for compatibility, diagnostics, and availability!

(4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!)


82 300SD 145k
89 420SEL 210k
89 560SEL 118k
90 300SE 262k RIP 5/25/2010
90 560SEL 154k
91 300D 2.5 Turbo. 241k
93 190E 3.0 235k
93 300E 195k
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  #12  
Old 12-01-2012, 07:05 PM
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GRRRR !! What happened to the pics ??
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1992 940T

"If you dont have time to do it safely, you dont have time to do it"

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  #13  
Old 12-01-2012, 07:40 PM
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Quote:
Originally Posted by TnBob View Post
GRRRR !! What happened to the pics ??
Pics are working on my end.. They are hosted on imgur.com, they might have been under heavy load at the time you viewed them. Try again, should be ok
__________________
Cruise Control not working? Send me PM or email (jamesdean59@gmail.com). I might be able to help out.
Check here for compatibility, diagnostics, and availability!

(4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!)


82 300SD 145k
89 420SEL 210k
89 560SEL 118k
90 300SE 262k RIP 5/25/2010
90 560SEL 154k
91 300D 2.5 Turbo. 241k
93 190E 3.0 235k
93 300E 195k
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  #14  
Old 12-01-2012, 07:51 PM
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I have seen that kind of contact damage when the battery is weak. Low voltage and high current.
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  #15  
Old 02-08-2021, 09:29 PM
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Hello
I have experienced the following symptoms on my 1983 300TD
While driving in the dark, the headlamps would dim, the fan would slow down intermittently, so something was drawing heavy current for a few seconds and then it would disappear. This intermittent current draw could go on for quite some time.


I heard a clicking noise in the front of the steering wheel in the engine compartment and discovered that it was the glow relay that was turning on intermittently while the car was running.

On opening the relay I have noticed the contact to the outside live +ve was very poor so I cleaned that all up.
I have the same kind of fusing going on on the left contact point as pictured above.
Is there anything else I can test on the circuit board that would indicate a faulty timer?

Why on earth would the relay turn on when the engine is running?

Notes for information:
Startup glow is normal and the light goes out
No problems cold starting
Battery is new
Alternator is charging at 14.5 V

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