MB truck electric questions

Hello!

I have a 93 917 AF and I'm currently in Northern California, USA and my flashers just went out last light. No turn signal or hazards. I did toggle the hazards and go the blinkers to work momentarily, but a few minutes later, it was back to nothing. I checked my fuses and they are all ok. Getting power to the fuse line 7-9, one of which I believe involves the turn signal circuit. In the dash, left to the glove box is a fuse panel. I swapped around the 3 relays to see if I identify a faulty relay but that didn't do anything. I'm pretty limited with electrical/volt meter skills. But I used the ohm reader to check to the two vertical plugs and the relays and it's reading --.3.

But I'm getting an odd click that has been intermittent at what I think is a control module when I turn the ignition power. I'll see if I can post picks of the module but it's marked as Hella unit # 014 545 74 32. I'm not sure if this is the culprit and if it is, where I might be able to source a replacement.

So far I've checked all the external bulbs minus the right front and relays in the dash and they all seem ok.

2B83DE2E-1F76-4012-A627-580DAB73E227.jpeg


I have a gut feeling this a small problem like a loose wire or short somewhere that will be hard for me to track down. I'm assuming if it was a bad/loose ground, I'd have a multi-system failure.

Are there places I should be checking?





In another unrelated matter, I'm also looking for OEM mounting hardware for the alternator. The pivot bolt snapped recently and it looks like someone has replaced the OEM tensioner hardware at some point. I have a working solution for now, but I'm trying to get things back to OEM specs for longevity/continuity.

Any help would be appreciated!

Thanks in advance!
 
Last edited:

MogsAndDogs

Member
Scott at Expedition Imports is up there in the bay area. He deals mostly with Unimog but there might be some crossover and he probably knows the best way to get parts from MB up there.

 
Thanks, I had pulled over at an auto-electric shop and a guy there thought that was the culprit but I was kind of wondering. I'll edit the original post to make this more clear. I'm pretty limited with any electrical skills but maybe someone can chime in and shoot me towards the right direction.
 

Joe917

Explorer
Something I have been caught out on is assuming a mechanic sees that it is a 24 Volt vehicle.
I would add some large lettering by the fuses. 24 VOLT VEHICLE
 

VerMonsterRV

Gotta Be Nuts
My guess is it is a relay, can you remove the electrical panel cover and have someone else operate the blinkers while you are at the panel listening for the click? On the back side of our panel is a schematic saying what each fuse/relay is for. I think the blinker one is larger than the others.

I just did a quick Google search for "LK/LN2 blinker relay". This is what came up on eBay Hazard Lights Relay FEBI For MERCEDES Lk/Ln2 Ng Sk -98 0025446432 | eBay . This one also Hazard Lights Relay 0015447432 For MERCEDES-BENZ LK/LN2 NG SK T2/L NOS GENUINE | eBay , it is in Oregon.

And if you already don't own the EPC/WIS on a laptop I highly recommend getting it. You can look up any part using your VIN, plus it has the workshop manual for procedures, specs and needed tools. It can be bought/downloaded from eBay for little money. I have learned a lot about our truck with it and is invaluable if you do take your truck to a shop that isn't used to these trucks. Owning an old Mercedes truck in the USA can be challenging.

If you want to post a picture of the alternator mounting. If I remember right your truck has a rather large alternator so it probably isn't like ours, but I can compare. Ours is a pretty simple rod with a threaded end, but our truck came with the 55amp alternator which I have upgraded to a modern 100amp one with 2 internal fans.
 
Something I have been caught out on is assuming a mechanic sees that it is a 24 Volt vehicle.
I would add some large lettering by the fuses. 24 VOLT VEHICLE

i had that same problem. I taillight bulb when out about a month after I got into this. I used the last spare and bought 3 more to have in hand. I took the old bulb a shop and asked them to match it. Several months later, I another bulb went out. You can imagine what I was thinking when I went through the spares within seconds. I read the voltage and was totally confused. Until I inspected the bulbs and saw I had been sold the wrong ones! :)


I’m still trying to track down this flasher issue.
My guess is it is a relay, can you remove the electrical panel cover and have someone else operate the blinkers while you are at the panel listening for the click? On the back side of our panel is a schematic saying what each fuse/relay is for. I think the blinker one is larger than the others.

I just did a quick Google search for "LK/LN2 blinker relay". This is what came up on eBay Hazard Lights Relay FEBI For MERCEDES Lk/Ln2 Ng Sk -98 0025446432 | eBay . This one also Hazard Lights Relay 0015447432 For MERCEDES-BENZ LK/LN2 NG SK T2/L NOS GENUINE | eBay , it is in Oregon.

And if you already don't own the EPC/WIS on a laptop I highly recommend getting it. You can look up any part using your VIN, plus it has the workshop manual for procedures, specs and needed tools. It can be bought/downloaded from eBay for little money. I have learned a lot about our truck with it and is invaluable if you do take your truck to a shop that isn't used to these trucks. Owning an old Mercedes truck in the USA can be challenging.

If you want to post a picture of the alternator mounting. If I remember right your truck has a rather large alternator so it probably isn't like ours, but I can compare. Ours is a pretty simple rod with a threaded end, but our truck came with the 55amp alternator which I have upgraded to a modern 100amp one with 2 internal fans.

Thanks for the response!
I’ve pulled the dash panels and did a visual inspection of the connections at the hazard switch, turn stalk, looked at the fuses, relays. There are 3 metal relays that I checked using my limited volt meter skills. I’m getting .3 ohm across the vertical spades. Behind that panel, is what I believe to a flasher control box with an additional relay that had similar ohm readings.
I also swapped the 3 metal relays around to see if that made any changes but it did not.
 

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Just had an electrician look at it and he believes this part has failed. He advised replacing this. It's the black HELLA control box that the pictured relay plugs into. Relays seem to be ok.
Any ideas where I can source one?

thanks!
 

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VerMonsterRV

Gotta Be Nuts
Just had an electrician look at it and he believes this part has failed. He advised replacing this. It's the black HELLA control box that the pictured relay plugs into. Relays seem to be ok.
Any ideas where I can source one?

thanks!
My guess is it will have to come out of Europe. From past orders I have found that ordering from either the UK or Latvia works well. Seems ordering from Germany can be hit or miss (I am still trying to sort out all the parts for the brake refurbish, still waiting on 1 set of linings). If you go to eBay.co.uk and search for TBB35 you will see several of them tbb35: Search Result | eBay . You may have to ask about shipping to the USA but I usually have good luck with UK sellers.
 
I was able to find a new one in Europe and it’s hoping to have it sooner vs later. But we all know sometimes ******** gets held up in customs. I’m also crossing my fingers this resolves it.

When I put my parking lights on, my taillights e illuminate but not my front fender or bumper markers.

Anyone know if that confirms or rules out the part I’m replacing is the source of this problem?


Sent from my iPhone using Tapatalk
 

Iain_U1250

Explorer
Not sure if this will help, but on the Unimog, the Hazard switch supplies the power to the turn signal, so if there is anything wrong with one of the contacts on the switch, you lose your indicators. YOu can take the switch apart and clean the contacts, but what out for the tiny springs and little contacts, lose one and you are up for a new switch.
 
Not sure if this will help, but on the Unimog, the Hazard switch supplies the power to the turn signal, so if there is anything wrong with one of the contacts on the switch, you lose your indicators. YOu can take the switch apart and clean the contacts, but what out for the tiny springs and little contacts, lose one and you are up for a new switch.

Thanks, that does help understand the circuit better. I think it's the same on our rigs. I did check the contacts behind the hazard switch (spade male/female connections), and they seemed ok visually. I did not take apart the switch.

Do you know if the circuit goes through the hazard switch before or after the fuse panel? I'm getting power at panel. The prior owner (Joe) has been really helpful and left the diagrams for me. But I'm ******** at reading old circuit maps.
 

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