83 300SD electrical issue - PeachParts Mercedes-Benz Forum

toomany MBZ · #1 07-21-2013, 03:49 PM

My (reman) alternator is killing my battery.

On the back of the alt is the regulator, good brushes. What is the black circle that is riveted to it?

And another "box", rectifier? See pic.

My voltmeter reads 13.1 at rest and 12.27 running.

Any help is appreciated.

The epc says part not found when I punch in the number for the "rectifier".

SD Blue · #2 07-21-2013, 04:28 PM

That is a capacitor for noise suppression. It is unlikely to affect the charging system. Are you getting a red "battery" light in the run position before turning to start?

toomany MBZ · #3 07-21-2013, 04:50 PM

Thanks.

No, now that you mention it, no.

Would a failed dash bulb possibly be the cause of my issue?

SD Blue · #4 07-21-2013, 05:08 PM

A failed bulb can give you a no-charge situation. The alternator field excitation comes from Battery-Ignition Switch-Charge Indicator Light-Alternator (blue wire). With the alternator disconnected, you should read +12Vdc on the blue wire, and ignition switched to RUN.

If you are not getting other warning lights as well, you may have an ignition switch issue.

toomany MBZ · #5 07-21-2013, 05:13 PM

Blue wire on block terminal, yes?

Currently unable to remove dash cluster, it doesn't just push out from behind like a 123.

SD Blue · #6 07-21-2013, 05:18 PM

Yes, the blue wire should be at C105 terminals on the RH front fenderwell.

JamesDean · #7 07-21-2013, 05:18 PM

Quote:

Originally Posted by toomany MBZ

Blue wire on block terminal, yes?

Currently unable to remove dash cluster, it doesn't just push out from behind like a 123.

Grab a coat hanger, and bend an end to a hook shape. Insert it between the dash and the cluster. Turn so that the hook grabs the cluster and try removing that way.

126 clusters are easier to remove than 124/201s and I would imagine 123s. No pesky speedometer cable to deal with.

toomany MBZ · #8 07-21-2013, 05:32 PM

SD B, alt unplugged, the blue wire and where to check for 12v?

JD, coat hangers are no match for this cluster.

toomany MBZ · #9 07-21-2013, 05:37 PM

I put the red lead on the blue terminal and the black lead on the negative battery, I get less than one mV. When I put the the black lead on the positive terminal I get -13.11v.

funola · #10 07-21-2013, 05:39 PM

With key on, ground the blue wire. Battery light should go on otherwise you have a fault in that circuit.

toomany MBZ · #11 07-21-2013, 06:02 PM

Okay, will need a helper. Not one available currently.

cho · #12 07-22-2013, 03:29 AM

Quote:

Originally Posted by toomany MBZ

JD, coat hangers are no match for this cluster.

also you can damage the cluster,I use to remove left dash speaker and just push the cluster out by hand from behind.

.

Stretch · #13 07-22-2013, 03:57 AM

It probably isn't that thing in the picture causing the trouble but just in case you need the information the only lead I can find on the internet is something posted by user "Govert" over on a Dutch site =>

http://www.w123club.nl/fluit-toon-autoradio-t14001.html

(About half way down the page)

(I searched for 0310024062 Beru)

JamesDean · #14 07-22-2013, 08:59 AM

Quote:

Originally Posted by cho

also you can damage the cluster,I use to remove left dash speaker and just push the cluster out by hand from behind.

.

I've used this method multiple times on at least 6, w126 cars and never had a problem with removal or damaging the cluster.

The factory tool is very similar. Perhaps a bit more digit than the coat hanger.

Removing the speaker is just unnecessary.

toomany MBZ · #15 07-22-2013, 09:08 AM

After viewing the video in a similar post, I'll need a helper to ground the blue wire to test the battery light. I would like to pull the cluster (clock and odo don't work and I have another cluster) and will need a set of the tools above, I'll check the rent tools section, but if anyone sees this, PM me.

I absolutely cannot push that darn thing out from behind.

Thanks Stretch, but I don't understand that language.