#1 Battery light on dash is on all the time, however it gets brighter/dimmer depending on how much draw I'm producing (lights, turn signals, blower fan, etc.). MB mechanic says this is the alternators exciter diode going and to be prepared to replace alternator. I have my replacement alternator waiting in the back seat.
#2 When the car was running, every six seconds I would hear a click and then my headlights would flicker(if on). I think(???) this is the same timing as the intermittent wiper setting, and the click seems to be coming from the right location for this to be the relay for the combination switch which I just replaced 6 months ago. Would the relay be activating even if I dont have the wipers turned on?
#3 Before last night I have had some problems getting the car to start. I would turn the key to on, and use my pull start to activate the glow plugs, and when I go to pull the starter, everything would go dead. No lights, no dashboard, no nothing! Then all of the sudden everything works, start the car, no problem( of course now I've already called someone to pick me up from wherever I am stranded). MB mechanic says first check battery ground. So, I try to remove (-)cable from where it bolts to chassis. It is rusted quite through and I'm thinking maybe thats the problem? I can't yet get the bolt off, but once I get a ride back to my office I will apply a "bigger hammer". But what do I do once I've removed it? If indeed that part of the frame has rusted through, where should I reconnect my ground? Also (maybe this should be item #4), now when I try to start the car, I get power when I turn the key to position 1, but when I turn to position 2, everything dies. Could this in fact be a bad ignition switch instead of a battery problem?
My current worry is that I have more than one thing broken here. I don't know where to start(pun intended) problem solving this. Any advice will be received with much gratitude! Thanks
#1 Battery light on dash is on all the time, however it gets brighter/dimmer depending on how much draw I'm producing (lights, turn signals, blower fan, etc.). MB mechanic says this is the alternators exciter diode going and to be prepared to replace alternator. I have my replacement alternator waiting in the back seat.
#2 When the car was running, every six seconds I would hear a click and then my headlights would flicker(if on). I think(???) this is the same timing as the intermittent wiper setting, and the click seems to be coming from the right location for this to be the relay for the combination switch which I just replaced 6 months ago. Would the relay be activating even if I dont have the wipers turned on?
#3 Before last night I have had some problems getting the car to start. I would turn the key to on, and use my pull start to activate the glow plugs, and when I go to pull the starter, everything would go dead. No lights, no dashboard, no nothing! Then all of the sudden everything works, start the car, no problem( of course now I've already called someone to pick me up from wherever I am stranded). MB mechanic says first check battery ground. So, I try to remove (-)cable from where it bolts to chassis. It is rusted quite through and I'm thinking maybe thats the problem? I can't yet get the bolt off, but once I get a ride back to my office I will apply a "bigger hammer". But what do I do once I've removed it? If indeed that part of the frame has rusted through, where should I reconnect my ground? Also (maybe this should be item #4), now when I try to start the car, I get power when I turn the key to position 1, but when I turn to position 2, everything dies. Could this in fact be a bad ignition switch instead of a battery problem?
My current worry is that I have more than one thing broken here. I don't know where to start(pun intended) problem solving this. Any advice will be received with much gratitude! Thanks
First thing, generally the battery ground goes to the engine block. Plus there will be a braided wire ground going from starter to chassis (completing the whole ground circuit battery/block/chassis. Then see what you have. You may well have some relay problems going on, but see if you do after repairing ground as the poor ground may be causing this problem also. I suspect a previous owner changed the battery to engine ground to the battery to chassis you presently have. Include the model and year of car you have in your next posting. You may also have a bad ignition, but don't worry about any of that until you have good grounds. I'd even wait on installing the new alternator until the ground situation is fixed, as it's circuit also necessitates a good ground. I'm not aruging against your mechanic, your alternator is likely bad, but fix the grounding system number one. Also, what kind of shape is your battery in? Make sure you remove the connector's from both posts and clean thoroughly. It would also be a good idea to remove the main power cable to the starter and an the starter's braided ground wire on both ends.
I believe you will find that the battery grounds to the body (right below the battery).
You could also put a block ground on it,I may do that to my 220D.
There might also be a voltage regulator on that model,mine sits on the passenger side of the wheel well.
Trouble shooting electircal probs is not much fun,but the grounds are where i would start with it too.
Thank you Ralph69220d, and Abadox. The ground was part of the problem, the alternator was second. The ground on my 76 220D (W115)was originally to the chassis. We had to move it due to rust. The exciter diode was still lighting even after the ground was fixed, so we replaced the alternator as well. I am very fortunate to have a MB dealership in the city that I live in that has a service advisor who has over 20 years of experience, and has owned many W115s and W123s. I have had extremely reliable service there over the years. I've never brought in a problem more than once. What I really love is that the guys there talk to me and explain things,they've even verbally guided me through a repair or two! I would have worked on it more myself, I have no garage and it has started to snow here in Eastern Washington. Thanks for the great advice...this forum is the best!!!
yeah i just got back my 84 300D today from the mechanic --i had the same problem as you. When I turned the key, the panels would light but when i tried starting, everything dimmed and it wasnt even cranking...
turns out there was something wrong with the alternator. Be sure your mechanic checks the wiring and the circuits as old cars like these, as strong as they are, are prone to electrical problems
While we're on the topic of w123s, can anyone help me figure out why the defroster wont work? Also, my glow-plug light up doesnt light, and according to the owners manual, failure to light up means the glow plugs are defective ---the car has been starting fine but i want to ensure my glow plugs are working....
yeah i just got back my 84 300D today from the mechanic --i had the same problem as you. When I turned the key, the panels would light but when i tried starting, everything dimmed and it wasnt even cranking...
turns out there was something wrong with the alternator. Be sure your mechanic checks the wiring and the circuits as old cars like these, as strong as they are, are prone to electrical problems
While we're on the topic of w123s, can anyone help me figure out why the defroster wont work? Also, my glow-plug light up doesnt light, and according to the owners manual, failure to light up means the glow plugs are defective ---the car has been starting fine but i want to ensure my glow plugs are working....
any advice?
From my experience with two 123s the glow plug lamp sometimes will and sometimes will not light when you have a bad glow plug. The car might start but chances are it will run rough until the cylinder with the bad glow plug comes up to temperature on its own - at that point it runs as if there was no problem. If you have an ohm meter, disconnect the glow plug relay and check the resistance of each glow plug by putting one lead to ground and the other lead on the nut that fastens the wire to the glow plug. Do this separately with all five (300) or all four (240) glow plugs. If you only have one bad one, you will see a noticeable difference in the resistance from the good ones to the bad. This will help isolate the bad one and avoid having to change them all at once. On the other hand, they are relatively cheap and tend to go at similar age so if you have a bad one now, you will have another one go bad before too long. Hope this helps.
whats really funny is the self-healing nature of this car....today was freezing cold (Im in DC now for college) and it was below freezing. The car cranked but didnt start so i turned the choke...the bloody glow-plug lights just suddenly worked...!!
for the record i have an 84 300D which my parents brought from germany (my dad was a yuppy)
21 years later (cars just a few months older than I) its mine...very solid, the thing drives like a truck and i love that its 5 speed manual
i could go on an on...my only complaint is those cold morning startups with the smoke..
are there any special fluids that make diesel easier to startup? i had the car get basic 'winterizing' but any other solutions?
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