R129 Indicator problem

[Flying Scot]

Just as i was sure i had 'most' of the wee electrical problems sussed out (a dirty/worn switch/connector block on the ignition switch) well what do you know the car threw me another wobbly.

My partner reported a warning light on the dash on yesterday - a bulb failure one - and on further questioning i discovered that the L/H indicators were not working properly.

She arrived home about midnight tonight so i had a wee lookie and sure enough the L/H/F indicator and the L/H blind spot indicators were not working and the rear one was flashing at double rate.

Well i know the double rate flash is a bulb gone but on pulling the bulb it looked fine. BUT as it has a funny asymmetric pin orientation i could not replace it with a spare so i swapped right and left side bulbs. Damn blast curses the bulb was OK so i thought it could be the blind spot bulb but after swapping them nope it was fine too.

Actuating the hazard warning switch all bulbs light EXCEPT the N/S/F and N/S blind spot indicator lights.

Fuses are OK if you pull the fuse nothing works.

SLIGHTLY to SERIOUSLY MYSTIFIED

HELLLLLP

way past bed time

thanks in anticipation

 

[television]

I would have though that a wire was broken around the fuse control box area

 

[Flying Scot]

I would have though that a wire was broken around the fuse control box area

Hi Malcolm i cant see that myself - I suspect that there is some sort of connector around the area of the blind spot indicator that connects the front indicator lights to the rear indicator lights - locating it is going to be the issue

Where can i find a wiring diagram with the location of all the connectors? The Russian site?

 

[television]

You have had problems with the N10 relay and that is where they come from.
Its hard lifting that fuse / relay holder out of the case, but it has to be there.

I can try and check on the colours, but you have them already by lookinr in the tail lamp and front indicator, as long as the front one is joined to the rear it does not matter

 

[television]

Thinking on this it may be the ground wire that has come off,

You can try this by taking a good wire that is joined to the chassis and touching it onto the outer part of the front NS indicator

 

[Flying Scot]

You have had problems with the N10 relay and that is where they come from.
Its hard lifting that fuse / relay holder out of the case, but it has to be there.

I can try and check on the colours, but you have them already by lookinr in the tail lamp and front indicator, as long as the front one is joined to the rear it does not matter

i think you are kunfoosed Malcolm ALL my intermittent electrical problems (no headlamp flashers no wipers and no indicators) would appear to be connected to the ignition switch - when i wiggle the external connector on the steering lock barrel - things are good for a few weeks. I was just about to order a new (internal) switch mechanism and replace it and then this one pops up - i will have a wee look at the possibility of a bad/broken earth connection this evening and report back ASAP.

thanks again

 

[Flying Scot]

CRACKED IT

more info soon with pictures

 

[television]

CRACKED IT

more info soon with pictures

Good man, do you want a job

 

[Flying Scot]

OK the problem was a 'series' of bad connections in a four way in series connector string.

BULB <-> BULB HOLDER <-> M/F BSF Connector <-> FEED Connector


THE FIX

Cleaned every connection the bulb holder was grotty the female side of the M/F BSF Connector was a bit loose and as i could not tighten that i ovalised 'slightly' the pins on the bulb holder i will need to look into tightening up the female side of this connector but i needed a much smaller screwdriver/tool
than i had to hand tonight.

OK

Here is what exists behind the front flasher lens on a SL500 1995 R129

From the lamp to the feed wires we have

1. An orange bulb with offset pins – these look like they are offset at 120 degrees.

2. A Bulb holder that locks into the lens with a twist at the other end it has two male pins (feed and return) with a polarising pin so you cant connect the connector (3) wrongly the connector (3) has a semicircle cut out to take the pin.

3. A black hard plastic connector with male and female pins female for the bulb holder and male for the feed and return this connector has two wires going from the middle of the connector/pins between the male and female ends these two wires go to the Blind Spot Flasher (BSF) this connector is also polarised.

4. A black hard plastic connector with two wires at one end - these are the feed and return to the front flasher lights – and two female connections at the other end this connects to the M/F BSF feed this connector is also polarised



THE ASSEMBLY

THE BULB

The Bulb Holder - Front then Rear

Connector 3 & 4 assembled and disassembled

I did of course FIRST check for a good earth and got One Ohm on my Beckman DVM - it needs calibrated as it got the same reading when i placed the probes one inch apart on the alloy block of the ABS control module.

AND the rain stayed off too

wooooooo hoooooo dun and dusted

 

[television]

David,, after all this work, please don't go around flashing to celebrate

 

[Flying Scot]

David,, after all this work, please don't go around flashing to celebrate

he he well you see i have the car here now and SWMBO wont be here till Friday evening at the earliest so you just never know - certainly i will be burning some rubber

This weekend i should have the STD MB 8 Hole wheels back from the refinisher so if the weather is nice i might get them on and take a few pics.

 

[Flying Scot]

Well they are on the blink AGAIN N/S/F and N/S/F blind spot dead - kaput - no working - however with no load i have 12 V intermittently in time with the other one flashing at the connector to both N/S/F indicator lamps - but under load with one or other or both of the bulbs in circuit ZILCH

hellllllllllllllllllllllllllllllllllp

please

thanks in anticipation

 

[television]

Well they are on the blink AGAIN N/S/F and N/S/F blind spot dead - kaput - no working - however with no load i have 12 V intermittently in time with the other one flashing at the connector to both N/S/F indicator lamps - but under load with one or other or both of the bulbs in circuit ZILCH

hellllllllllllllllllllllllllllllllllp

please

thanks in anticipation

If you have have 12 volt with no load david it is the ignition switch surely

 

[Flying Scot]

If you have have 12 volt with no load david it is the ignition switch surely

I dont get your logic Malcolm.....................FOUR of the indicator lamps are flashing fine all of the O/S ones and one N/S one the N/S/R - TWO front ones on the N/S/F are not................when i check with a multimeter the two wires behind the headlamp and Indicator (see pictures posted previously) with the feed/return to the N/S/F indicator and N/S blind spot flasher - unpluged from both i can see 12v intermittently - this is in time with the other lights flashing. I am using the hazard switch so i dont need to have the ignition on. BUT this is that same symptom/problem/fault with ignition switched on and the indicator switch on the L/H turn position. BUT when i connect either or both of these lamps the N/S/F indicator OR the N/s blind spot lamp to this feed i get 0V

None of this makes any sense to me logically so i need a wiring diagram to work though this / these circuits wire by wire connection by connection - just by cleaning tightening these connections 'last time' this appeared to fix this however that was obviously not the real fix.

 

[television]

OK the hazards are not wired via the relay Have you checked the N10 for dry joints or bad relay,,with a poor connection often 12v is there with no load, but breaks down under load

Is you relay a 140 820 71 26

 

[Flying Scot]

where is N10?

i was poking about in the relay box behind the fuses after removing the lid and around the big black rectangular relay have it in my hand at the mo

IT IS MARKED AS FOLLOWS

MERCEDES BENZ
129 820 10 26
05 3600 00
12V 2(4) x21W
max 6x32cp
DOT SAE
J590e/J945b 88
719090
>PA /MF <

 

[Flying Scot]

OK after looking at another post after doing an N10 search and seeing a picture posted by you Malcolm i have figured out i dont have the N10 in my hand and the N10 is the bigger longer black one nearest to the centreline of the car

BUT i cant pull that one out it has two lugs on the side and what looks like a guide rail on the outermost side is this relay just plugged into its connectors and is it just the friction/stickion of the pins that is holding it in and stopping me from pulling it out?

Also IF i get it(N10) out how do i take its cover off to check for badly soldered/cold joints? I cant see how to get the cover off this one i have in front of me unless i took a dremel to it with a wee circular saw blade.

thanks in anticipation

 

[Flying Scot]

Even more confused now after reading other posts on a N10 search it would appear i have got the N10 relay in my hand 1298201026

I managed to get the top off rather easily with a very sharp knife down the glue line but cant see how to get the internals into daylight/into my desk/hand i can see two PCB's with a ribbon cable joining them on their top edge - that is it so far GRRRRRRRR

 

[Flying Scot]

Pictures

well what do they say about pictures and words

 

[television]

David that is the early version ,,I will photo copy an article on checking that for you


The common fault is where the relays are soldered on,,look for a ring around the pins where they are soldered on, or just re solder the joints on the relay, do apply a fluxed cored solder