there really needs to be a little extra wire so its not strained
Ive ordered a new 3 pin alternator plug I just need to know what gauge wire I need for the two output wires and for the exciter wire?
Also what size lugs etc for the other end where the lead terminates at a junction box on the inner wing?
I don't really want to go to Mercedes as I can imagine a replacement lead will be a horrendous price and be a little tightwad in length just like the original :wink
Car hasn't moved for over a month because of this issue its high time I got it back on the road :eclipsee_steering:
Having to retype this as i cant edit my own post! Whats all that about? :eek
After months of my 230e playing up not charging the battery I have finally found out why
I want to repair this myself but need a little advice and a list of things I need?
In short it's my alternator lead,the exciter wire has a break in it causing an open circuit it literally makes or breaks with 1mm movement "wallbang"
Plan is to replace either the whole exciter wire or possibly the whole lead?
I think its broken because of strain and its barely just long enough
there really needs to be a little extra wire so its not strained :no:
Ive ordered a new 3 pin alternator plug I just need to know what gauge wire I need for the two output wires and for the exciter wire?
Also what size lugs etc for the other end where the lead terminates at a junction box on the inner wing?
I don't really want to go to Mercedes as I can imagine a replacement lead will be a horrendous price and be a little tightwad in length just like the original :wink
Car hasn't moved for over a month because of this issue its high time I got it back on the road :driver:
on a model w/ the M104 engine, the alternator-to-X4/10 B+ wire is 10.0 mm^2, the wires from X4/10 to the battery and to the X4/1 behind-the-dashboard power distribution connectors are each 8 mm^2. On earliy M103's, the alternator-to-x4/10 is a pair of 4mm^2, on later M103's, this was replaced with a single 8mm^2. On all of these, the D+ wire from alternator to X4/10 is 0.75mm^2
I would expect a 2.3 to be the same, but I don't have wiring diagrams for one.
Though I am grateful for the breakers yard suggestion I fear another used lead may be on borrowed time?
Thanks for all the info LeftCoastGeek
On a diagram I have it shows 0.75 for the exciter/warning bulb wire as you suggest but 2.5 for the output wires
Im a little confused though as my alternator as far as I know is 55amp on the 230e i think the 260 and 300e were 70amp
Looking at the properties of 2.5mm it suggests its around 30amp limit as my alternator can output 55 is that not too weak?
Or in the case of the two output wire models do there split the output?
Whatever I should have I think the best course of action would be to upgrade to a slightly heavier gauge?
I am learning so any information is gratefully received
How come the wire that goes from the junction box distribution to the battery is rated as it should be but the wire from the alternator to the junction appears to be under rated?
Well I replaced my broken wire today and I still have no warning lights or charging function
I fear the car will get scrapped or junked just because of this
Only done 70k Miles and this is its only issue but i cant get to the bottom of it
New Battery,Alternator,OVP nothing fixes the issue
I feel bad enough at the thought of junking my beloved car I am doing no harm using emoticons if I wasn't supposed to use them they wouldn't be available!
I am a new user so much for friendliness I have only been here a few days and had two complaints about emoticons and both times its been the same person
Well I replaced my broken wire today and I still have no warning lights or charging function
I fear the car will get scrapped or junked just because of this ...
Before you have your car scrapped :eek, try again with the lamp failure monitoring unit (N7) pulled out. It's the long relay-like unit in the rear compartment of the fuse box.
According to the circuit the ignition feeds 12v to fuse 5 from there it goes to pin 8 of the instrument cluster :wave:
From there it goes through the Alternator/Battery bulb out the other side through a diode and out at pin 9 :grin
Well on Run position of the ignition key I have 12v (well 11 as my battery isn't getting charged :big laugh at Pin 8 of the cluster plug but ii isnt making the trip back to the alternator I guess?
Really feel like giving up on a great car just because of this issue :crying
I haven't got a Charger,I have never needed one before,I guess its high time I got one?
Ive seen the U.S Model diagrams they are roughly the same but your charging circuit seems to go to fuse 7 our to fuse 5 apart from that its the same as you 300e model
I did note one thing though don't know if this is significant?
I removed fuses to clean contacts and forgot to replace fuse 5 :eek
On the turn of the key my battery light can on so it lights up on ots own without fuse 5 but stays on but refuses to light with the fuse installed?
To my mind the circuit needs to be grounded to make the light glow when its grounded through the alternator field the light glows then extinguishes and charging takes place.
Remove fuse 5 and it appears to permanently ground that bulb but non of the other warning lights glow :crying
the D+ terminal of the alternator, circuit 61 in DIN, goes to the small terminal in X4/10 near the battery box, and from there its the ALT light on the dash to the ignition switch to the battery.. if ignition is on, X4/10 pin 61, and the alternator D+ terminal should be at battery voltage.
the alternator's body is the ground. the regulator is part of the brush assembly on euro alternators, and its all on the + side. there's two connections, the B+ output which goes to the battery via heavy gauge wires, and D+ which goes to the ALT light in the dashboard and the ignition switch and the battery. another thing that can fail is the diode board inside the alternator
One of my non-mercedes old cars had charging problems that turned out to be a poor alternator ground. By using a volt meter and measuring voltage from the battery - to various other grounds, I was able to find this easily.
nah, I'm on the left coast, its only 1:50am now, and was 12:45am when I posted the above.
if I suspected the alternator ground, the first test I'd do would be to poke my voltmeter at the battery - terminal, and the alternator body/ground when the engine is running, or someone is cranking it over. if there's more than 0.1 volts difference, you have a ground problem.
and I'd test the rest o the operating voltages. X4/10 is the alternator terminal, right on the false firewall in front of the battery. the big two bolts are tied together and are circuit 30 (B+), and the small terminal on the end is circuit 61 (alternator D+)
test the voltage at x4/10 as I've said, thats the D+ circuit to the alternator, with the ignition on, it should be some voltage less than 12 but more than a couple volts. if thats good, then stop worrying about the dashboard battery light, and start checking the alternator itself. if thats bad, then check the dashboard light.
well, 11V is too low of a battery voltage, thats low enough that trying to start the car will damage the battery permanently. it needs to be fully charged before you do anything else.
Well I have removed both N10 and N7 relay (N10 was in the way)
I popped N10 back in but left N7 out turned the key and nothing has changed
I will check continuity better now the relay is out and I have cleaned up the pins as N10 was covered in green crusty stuff but N7 was clean as a whistle :wink
Don't know if I should open up either and re-tin the solder joints before putting them back in?
Don't know what to check next?
My bulb bypass?
Do still wonder if the circuit is not grounding as if I remove fuse 5 the bulb comes on and grounds itself (through another fuse I am guessing?
bulb bypass? better grounding of alternator?
Originally I thought this was an OVP issue dont even know how or when the OVP comes into this circuit?
... Do still wonder if the circuit is not grounding as if I remove fuse 5 the bulb comes on and grounds itself (through another fuse I am guessing? ...
Yes, me too … and N7 is just one of the possible culprits, via which a connection of the D+ wire to ground could happen. … I wish I could say that I’m sure that nothing happened to the (new) alternator.
You could check whether there’s a connection between the socket of fuse 5 and ground. The wires fused by it go to:
- N7, pin 9
- brake light switch
- lamp failure warning lamp e14 in the instrument cluster
- instrument cluster, pin 6 (voltage for several warning lamps)
- rev meter (pin 3 of the small connector)
- dome lamp control unit above the rear view mirror (pin 3)
I have one but if the voltages are there why would it be an ignition switch?
Not being confrontational it just makes no sense the switch is a switch when i turn the key i get voltage at fuse 5 and at pin 8 that's the side the ignition switch deals with so how can it be the switch?
Also don't have the strength to be talking steering columns out or ever dropping them.
I could probably get the the plug off my switch but doubt I could get the switch off
Its a no brainer in one sense as i have a brand new switch but fitting it thats another story
Its heartbreaking Ive always wanted a w124 and I drove this car 1000 miles with no issues just a couple of months ago.
Theres been so much done to the car
New Battery
New Alternator
4 New Tyres
New Exhaust
Propshaft Doughnuts
Engine Mounts
OVP
New Ball Joints
Transmission Fluid/Filter drain full including Torque Convertor
I don't want to give up on it but cannot keep putting money into it
I will try testing to see if there is continuity from fuse 5 to the ground but the car sits outside and the weather is terrible now so maybe later or tomorrow?
I have seen this exact symptom once before, and chased my tail on it . . . until I replaced the ignition switch. That's why I mentioned it . . . . trice.
No need to drop the column. That's just adding extra work and sweat. Just remove the cluster
One more thing, if the key and tumbler have never been replaced do it all at the same time since you have to disassemble the steering lock and these parts all work and wear together as one unit. Be sure to use brand new VIN# coded OE MB replacement parts.
WARNING: make sure you use the forum search engine to learn the workings of the lock. Improper assembly will cause the steering lock to jam permanently.
Tumbler and key are both fairly new I ordered them as the originals were in very poor condition so it would just be the switch need replacing...........
I am sorry but that scares me I cant see why you cant just put the key to position 1 pull off the plug and replace the switch?
Also having to drill the lock assembly off the steering column I am not up for that all risky stuff
I thought it was supposed to be easy ?
Cant see why if the key was turned to position 1 and the tumbler and key remained in place why the switch couldn't just be removed and replaced and connector reconnected?
I cant even drive it down to the garage to get them to do it :frown
Used the search engine cant find anything other than tales of misery and woe putting me off :crying
when you say continuity, how many ohms? was that with the ignition off ? the hot side of fuses 5-6-7 are circuit 15 from the ignition switch, so any loads across that circuit would provide a resistive path to ground. 0 ohms would suggest a hard short. a 12-15 watt lightbulb would be about 12 ohms (amps = volts/ohms, watts = volts*amps). etc.
So can I change the switch with the lock/tumbler in situ?
Do I insert key,switch to 1 wiggle plug out of the rear,unscrew switch,replace with new one with key still in place,insert plug and that's it?
still frightened about doing it and also theres not enough clearance to get the screws out?
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