Need relays for 1973 220 - PeachParts Mercedes-Benz Forum

BobDylan · #1 09-08-2011, 02:42 PM

Hello, I am new here and posted this in the technical category before realizing there is a seperate category for the good mercedes

of pre 1979. I am hoping someone will be able to help me locate or maybe give me some guidance on where to locate the 6 and 8 prong VDO brand relays. I have been having a bear of a time trying to locate them. Does anyone have any ideas or maybe know of a cross reference part. Also, even a full part nmber would help as my numbers are not complete on the oriignal stickers. The numbers listed are " 411.204/1/5" and "410 203/1/10". I just purchased this car and am trying to get her running and think the relays are at least 1 culprit.

Thanks all.

BobDylan · #2 09-08-2011, 08:37 PM

Hi I thought this picture might help. they are near the drivers sidewall under the hood. Thanks for any help.

meltedpanda · #3 09-09-2011, 12:17 PM

I think I have both let me look tonight

meltedpanda · #4 09-09-2011, 11:05 PM

0015421219 and 0005454432 are the ones I have but I think they may be for a 280 or for 6cyc. They look just like what you show

686point3 · #5 09-10-2011, 03:28 AM

Quote:

Originally Posted by BobDylan

Hello, I am new here.....there is a seperate category for the good mercedes

of pre 1979.
I just purchased this car and am trying to get her running and think the relays are at least 1 culprit.

Thanks all.

What's it doing ?or better what's it not doing ?.

My experience on the str8 forward carburated cars (4 CYL ?, WITH 1 Stromberg carb ?), a very simple design, it's usually like clogged fuel lines, old fuel, gummed up fuel system and carburator, or even points gap or condensor / ignition adjustment issues.........

stick another relay(s) in there that you don't know work(s) any better or worse would tell you what ?

Check
1. fuel issues,
2. ignition

That simple....

An answer back here would be nice as to how far you got and what the issues were , and what helped getting it fixed.

Thanks

Good Luck

meltedpanda · #6 09-10-2011, 09:42 AM

yup give us some details , I have had every nut and bolt off my ol gal.'
read here it may help -well documented 220 rebuild
1971 220

46,000 views and growing

BobDylan · #7 09-10-2011, 12:44 PM

Thanks all. I was told in the tech forum (that I posted in first before relaizing there was a vintge section) that the relays are for emiisions only and are not needed. Meltedpanda, I read quite a bit of your other post, sounds like you have been aorund the barn a few times with your car too!

Here is my story: I picked this car up for a great price from the second owner. She said it was working/ running well, but she got a new car, it sat for about a year and now it wouldnt start, etc, etc. My previous MB experience is with a 1967 200D (that I still have) and a '75 280C that never has had major issues, so please forgive any ignoriance I show in dealing with a gas engine MB.

Here is what she is doing, Simply put, she will try to start but not turn over. Here is what I know: 1) The battery is good 2)The starter is good (or else it wouldnt try to turn over right?), 3) the fuel pump is a newer aftermarket setup and is good (it fills the clear sight tube in the line when I try to start her). 4) The ignition coil is good (I ran it for about a week in my 280c to test) but does not put out spark (so it is not getting power right?). 5) the key turns over and starts the fuel pump, starter, etc. And that is it.

I am thinking at this point that the first thing I need to do is to figure out why the coil is not getting any power therefore not sending power/ spark out. Further down the line I may have fuel issues and spark plug and distributor issues, but first things first. The thing that strikes me as most odd is that there are only two tiny wires feeding the coil (one being a ground the other being a brown wire). Another thing that is odd is what the heck is that heatsink looking thing that about 10 wires are hooked to behind the drivers side headlight. It feeds some of the wires up to the coil and it looks somewhat corroded and I havent gotten a chance to dig into it, but testing the wires where they come from and the ends, it seems like everyhting that I can find is getting good electrical connection. At this point I am about to dig into the ignition to see if there is a wiring issue there and if there is a switch issue. Of course the person that I bought the car from made an off hand comment about how the original owner messed with a bunch of the wiring. Goodness knows what reason or what he did. Please stop me if I am not on the right track. THANKS!!

Mike D · #8 09-10-2011, 08:11 PM

There are two circuits leading to the positive side of the coil. One is the "start" circuit which supplies 12 volts when cranking. This circuit is usually fed from the starter solenoid. There is a "run" circuit which is fed through a ballast resistor by way of the fuse box/ ignition switch circuit.

Turn the key to the "run" position, dash lights come on and buzzer may sound. Check for voltage at the positive terminal of the coil. You should have between 6 to 12 volts depending on the condition of the ballast resistor.

Have someone crank the car while testing the voltage at the coil. You should show battery voltage dropping to the lower voltage when the key is released.

Start there.

BobDylan · #9 09-10-2011, 09:57 PM

Hi Mike, I am only getting 4.5 volts in start. During turn over it drops only marginally to 4.1. I think I am missing a positive lead my 280c has two and drops from 9v to 6v. Thanks.

Mike D · #10 09-11-2011, 09:32 AM

Yup. Sounds like you are missing the "start" circuit. The 12 volts adds a little extra ooomph to the coil for starting.

4.5 volts sounds a little low but that could be anything from corrosion on the terminals, variances in the voltmeter to not getting a good ground.

Check around the supply side of the ballast resistor. The two coil + lines usually are/were in the same harness at that point. It could be someone removed the wire because they weren't getting a voltage reading on it not realizing it was only active during crank. They could also have not replaced the wire at the starter during a replacement.

You could "hot wire" the +12 with a wire from the battery for starting testing only. Don't leave the wire attached for very long and remove it immediately if the car starts. You'll quickly cook the coil (10 minutes or less) if you leave it connected.

meltedpanda · #11 09-11-2011, 12:57 PM

your sure the coil is good? and the right one?

686point3 · #12 09-13-2011, 02:11 AM

Hey
looks like with that little push I got you going in the right direction.

I am not an electrical wizard, but it looks like Mike D has got a good idea here of what's going on.
That heat sink looking thing is the ignition modulator from what I know and they rarely go bad, but you surely cannot tell from the outside how it looks inside (which is the important part). You would have to test it to see if it works, looks alone won't do it.
I think it boosts your ignition spark, so the wear on your points is minimized.
(I never read up on this, and it's hear say, could be wrong altogether.
I am glad you're on your way.

Just for clarification:
Turning over an engine I was told means it cranks, but not necessarily starts (as opposed to turning the ignition key and no sound / either frozen motor or starter problem, there fore no cranking.)
I think what you meant was engine simply starts and idles (?)

good luck

Alex
in N L.A. county

BobDylan · #13 09-13-2011, 09:18 AM

Hi everyone. Thanks for all of the advice/ suggestions. So I started to wonder about the coil again and took it out and drove my 280C to work with it today. It looks pretty OE to me, it is a Bosch with light blue paint and an orange top with a (half gone) "transistor" sticker on it. So I think it is still safe to say it is good.

I tried to 'hot wire" the positive off of the positive battery cable to the positive side of the ignition coil.... and learned a few things

. 1) I needed to remove the "original" positive wire or I would get sparking, not sure if this is normal. So next time I will use alligator clips, but I was excited to try this and decided to use jumper cables. The engine still wouldnt start with the jump and during the process I arced against the positive wire and burned the wire off. Luckily the wire was just about a 6" pig tail that someone had put on so I simply removed this section. Only now I am not getting any voltage reading from the coil (first I thought I fried the coil, but I didnt, see above). So now I have to figure out what I did, but even though I wasnt able to get a volt reading (no helper around during hot wire) I think I need to find that start wire as Mike had said earlier. I will try to get some pictures up.

And to answer the question about the engine starting, I can open the oil filler cap and see that the camshaft moves when I try to start, thats about all that happens.

BobDylan · #14 10-10-2011, 10:09 AM

So I am working on this again and here is what I have found: 1) I switched the ignition switch out with my 280C and the 280 stared right up. SO its not that. 2) I put a battery charger to the positive side of the coil and still no spark from the coil.

Not sure what my next move will be. I KNOW I am missing a positive side coil lead. I have looked at pics on Ebay of cars for sale and the one good picture I was able to find looks like it showed a wire coming out of the distributor to the coil. My car has just one wire from the distributor and it goes to the the heat sink (forgot the name) behind the headlight where at that point it probably loops back up to the coil but it would go through a resistor and maybe I am losing power? I would love to see a close up of someone elses wiring on their car.....But even though I am missing a wire, shouldnt it have started off the charger?

daidnik · #15 10-10-2011, 03:57 PM

You cite a 280C & a 280, but the thread starts on a '73 220 that would be a W115 chassis.

Which car is it that you are trying to fix?

I ask this because I have a W115 '73 220 that is 'stock' with the electronic ignition switching box under the battery.

If this IS the config you are trying to fix, then I could probably offer something.