E34 Electrical Help

[Gabs]

I briefly covered my issue Here

Though here is the run down, I broke the cable that comes off the positive terminal that runs to the 80amp fusible link, the cable bounced off the terminal a couple times, I'm thinking this caused some sort of surge.

My issue is, My vehicle now has no power to Central locking, windows, wipers, washer pump, mirrors, heated seats, clock, radio, all no longer appear to be getting power.

I have replaced the broken cable with a copper starter cable of a slightly larger size, I've have an inline 80amp fuse replacing the fusible link. Have checked the fuse box under the hood for blown fuses with no luck. I also have gone as far as replacing the Relay Control Module, General Control Module and all 4 small yellow relays in the back (under rear set) fuse box. Back fuse box has no blow fuses either. I have also confirmed the cable under the hood after the fusible link shows over 12 volts, cant remember the exact number. So the voltage is not being dropped. I'm not sure where else to look, and have no idea how to trace this cable back to the modules, as i believe it travels through the body somewhere.

All that being said, the car runs just fine, headlights signal lights all work properly. My only conclusion would be possibly a 2nd fusible link hiding somewhere? Haven't heard of this on e34 though. Or the cable burned up somewhere? I have no idea please help. Going out to the car with my multimeter to see if I cant find any answers.

Edit in: I hope I'm being clear in my description, I've been awake nearly 26 hours, so bear with me.
Also voltage on that cable just before it goes towards the dash shows 12.15V

[Gabs]

Bump - Would I get more replies if I lied and said this is an e30?

I may have tracked this problem back to a 61.36 K3 relay under the hood, though BMW is closed on Sundays and NOBODY in my city stocks any BMW parts it would seem.

[keflaman]

I went through the electrical troubleshooting manual for your car, but electrical troubleshooting is not my forte. I was wondering if there was a common grounding point for the non-functioning systems that may have gotten damaged?

[DesktopDave]

I'd disconnect the battery & open up the fuse box.  An overload can easily damage a fuse connector.  Taking a quick look at the ETM also suggests that fuse 24 might be a culprit, the e34 body computer takes it's power off that circuit.

Could also be a damaged computer, hopefully not.  E34 electronic parts are cheap used but often broken.

[Gabs]

I don't think its a grounding issue, though I'm open to explore all ideas, haven't found a specific grounding point for these systems in particular. Fuse 24 has been replaced to no avail Dave. Does the e34 use a separate computer for the body electrical? I was under the impression the 2 modules acted as the main brain for body electrical. Though I haven't found much useful reads on this either, so I'm likely misinformed.

Well the relay in my fusebox that controls fuses 15-18(i think), it becomes unusually warm when the vehicle is operating, Ive also noticed blue heat type streaks on its 4 prongs. This relay can be removed and my vehicle still runs and drives fine without it. Leading me to believe this may be the main relay for the accessories, and that it is internally shorting causing heat. Aside from this relay, I've replaced every module, relay and fuse to do with Body electrical.

So I imagine it must be the culprit. I certainly hope so, because I've spent days searching for this relay, even the reputable German shops in my city could not locate this relay for me. So I had to bite the bullet, and go into my local BMW dealership, it took them nearly 20 minutes to get a part number, they had to search through electrical schematics as the part number on the relay was non existent these day.

All in all, they found 1 left in Canada and are overnight shipping it. At the cost of $43 Canadian, FOR A DAMN RELAY!!! haha but I'm hopeful this solves the problem, as I've been driving this vehicle through a canadian spring, without any electrical, and let me tell you its been hell on wheels. Its soooo warm out today too, and I cant even open my windows, leather has never felt so horrible

Anyway ill quit my rambling, thanks for the help guys, Ill let you know tomorrow hows things go.

[Gabs]

After replacing that relay and checking every fuse I can think of, im at a loss, I have no idea where to look anymore. Might just sell the car.
Edit: Just got my Hands on the ETM for this production year, hope fully I can track this down, though the relay I just replaced appears to be for the blower motor. Damn bimmerforums people steering me in the wrong direction *shake fist in air*

Edit #2: All my fuses for wipers, central lock etc. under the hood show 11.91V with key 2 clicks forward. The problem is the rear fusebox/modules are not receiving any power at all.

Edit #3: After ripping up the back carpet, I now think I understand the path these wires take. From the Fuse box, I believe these wires then travel through the drivers side all the way to the back Power Distribution Box in the rear. Below the first picture shows the white cover, these wires are directly behind it, the picture taken nearly beside the driver seat. The 2nd image shows the wires coming out at the rear and making its way to the modules and what not under the rear seat.

From what I've seen there is no fuses, or links of any sort along the way. I'm incredibly baffled as what to look at next. If the fuses in the front have power, where in the world is that power being dropped off. My next venture tomorrow might be directly powering the back distro box with a spare battery and cable with 50amp inline fuse. I'm damn closed to just selling this car.

I couldn't figure out how to resize these with IMG Tag, so ill just link to them.
http://cdn.anonfiles.com/1333569828676.jpg
http://cdn.anonfiles.com/1333569195480.jpg

[DanOKC]

I don't own an E34, but have 30 years experience as electronic tech & had to sort out electrical issues on my E30 (previous owner had wrong relay in one spot & a bad relay in another) & it was piece of cake for me, so maybe I can help. Your first thing to do, which you said you just did, get the ETM. Now that you have that, don't spend a dime on relays or chop wires etc.. You can do all your troubleshooting with a voltmeter.  I just briefly looked at the E34 ETM. My best guess is it's only a fuse or a relay. How I would troubleshoot is to read the ETM, follow the power distribution & measure for 12 volts at key points. Make sure your negative probe is on a good ground point, this is a must.
If the voltage is not there, look upstream closer to the battery. Pull fuses or relays & poke the positive probe of your DVM into both sides of the fuseholders clips or the appropriate relay clip & see if the 12V is there. Use the DVM's ohm function to test any fuse you suspect, or sub another known good fuse.  Like Fuse F37 30 amp at the rear power distro box. It feeds the general module via the general module saftey relay.

Do you have 12 volts on either side of the F37 fuse socket ?

If it were me, I'd print the pages of the ETM, makes it easier than flipping pages on screen on a PC, plus you can take them out to the car.   There are other tricks & tips I can suggest if you haven't fixed it by now. You also need a legend for which fuse is F37 etc... Print that out if it's not on a fusebox cover, find it online somewhere.

[Gabs]

No the problem is, I'm not getting any power to the back power distribution box. Literally every socket for the fuses reads 0v back there, I cant find any power going to that back box. Though from under the hood, all my fuses for these systems read 11.9 volts, which I'm told is normal for most of these systems. Power in the front fuses but no power in the rear is my problem. I still have yet to figure this out.

ill have to dig deeper at the end of the weekend, but for now I have to drive it as is. Also noteworthy, My cigarette lighter sockets work, key chime works, all my gauges work, but I believe these systems are independent from the systems currently not functioning.

[DanOKC]

OK, I understand you don't have any 12V at the back box, just as a tech, I read on forums & sometimes hear stories of, I didn't have my meter on a good ground, so I'm just saying, make sure you have a good ground before you read every fuse socket as dead. Without knowing which year & make E34  you have, I can't do much good looking at the ETM, as they have different modules etc.. per year and motor. So, I did a little web search & came up with this:  I copied this from bimmernut dot com, hope that's OK per forum rules:

#1 root cause for what you describe is the 80A relay. Common fault. It is near the battery under the rear seat in most e34s, but on M20 and M50 powered cars it is in a big black plastic case on the frame over the front spring support. These fuses can die with age and look okay, and intermittently fail as well. Check the fuse on the firewall and also for inline fuses on the thicker wires that come from the battery. There may also be one under the backseat, I can't remember.

[Gabs]

I'm diagnosing a 89 525, M20. I am almost positive I'm using a good ground, I will triple check tomorrow. My battery resides under the hood and not under the seat. I've yet to come across the 80 amp relay you speak of, though have replaced the 80amp fusible link that resides in the location you speak of. I can only imagine there is an inline fuse hiding somewhere near the firewall or behind the blower cover, though it wouldn't seem to make much sense, as I don't think I'd have proper voltages at the front fuse box if this were the case. Ill report back tomorrow after I attempt retrace the entire run of all the cables.

[DanOKC]

That post I copied about the 80 A relay may only be for cars with a 2nd battery, or it may be he was calling the 80A fusible link a relay.

Maybe this will help, from looking at 89 E34 ETM and Russian  93 525 version of etm, F37 30A  and F47 30A (windows), F30 7.5A (windows),  F42 30A (Seats), F43 30A(seats), F36 30A ( radio), all in rear fuse box  are hot at all times. Front box, also hot at all times: F32 7.5A & F33 7.5A (door locks), hot only in run & start: F12 15A (mirrors)
A bunch of stuff goes through F37 in back box, so I’d concentrate on that one the most, if you get 12V to that fuse, it goes from there to a relay in back box before it goes anywhere else.

And, that 80A fusible link you replaced, it shows 1 wire from positive terminal of bat going to it, and 2 red wires leaving it, one to front box, one to back box. I'd concentrate on this the most.

Also on my 318 when I found the relay mixup, they were both the same color relay, but had different part #’s, since you said you replaced relays already, I mention this because it’s easy to overlook also. Not sure where to tell you to verify the right relays, but I assume you still have the original relays.

[Gabs]

Excellent Information DanOKC, I haven't had a chance to look at this problem, as the weekend was quite busy. I have a few hours Today to look into it.

A bunch of stuff goes through F37 in back box, so I’d concentrate on that one the most, if you get 12V to that fuse, it goes from there to a relay in back box before it goes anywhere else.

From my previous readings, I Believe I was not getting any voltage on F37, I will triple check that today while im out there.
EDIT IN: Now that I look through my ETM, the Charts do not list an F37. I have F47. Also F44 that also seems possibly relevant to Body electronics.

And, that 80A fusible link you replaced, it shows 1 wire from positive terminal of bat going to it, and 2 red wires leaving it, one to front box, one to back box. I'd concentrate on this the most.

VERY Interesting, I was not aware one was for the front and one was for the rear. What I can tell you though it that before both these wires go into a rubber gromet on the chassis towards the dash, they both read 12V+, telling me that the connection at the link is good. Problem is, No where do I see this same cable size heading towards the the rear box up the drivers side. I'm also not sure where these 2 cables go after entering a gromet in the body under the hood.

Another Edit in: While I sat here finishing off breakfast, It also dawned on me that, last I had checked the fuses in the front box did show voltage. So I'm really going to concentrate my time today back tracking the other positive line, try and cover its every move, so to speak. In my head I keep thinking, there must be a blade fuse or something along the way I haven't found or at least something along those lines.

OH! and another thought just came to mind. Over the last week, I've been getting "Open Door" warnings on my dash quite intermittently, I even pulled over many times and double checked all my doors. Not sure what this indicates.

That being said, I have a funny feeling if I pull the front "blower Cover" board thing, I may discover these wires coming across, one going to front box and the other naturally to the rear.

Thanks for Combing the ETM for me DanOKC, much much appreciated. I have much trouble reading through the diagrams personally, though its my first time ever viewing an ETM.

Will report back in A couple hours.

[Gabs]

Well That felt like an another wasted couple hours. With little to no results at all. I don't appear to have consistent power at the rear box, though before I started pulling at things I swear I measured a 1.26v on all the fuses back there, I'm not 100% sure maybe I received a false reading, but I'm quite sure there was a point during today I found 1.26v on my fuses. Though after poking around at things I retested and found 0v on all fuses. Also the "Open Door" warning on my dash is no longer appearing.

As stated before both Positive wires leaving the 80amp link read 12.31v, as shown. I've taken pictures, but not sure they explain anything.


Also this is where these 2 wires leave my sight behind a grommet in the body.


My question is at what point do these junction with whatever they junction with? Because up both sides of the car, there is No cable of this size. Also pictured below is the main mass of cables going to the rear box, though the thick red cable simply runs across the back seats to the old location of the battery, though under the power box it does junction with a bunch of smaller red cables that appear to come from the front of the vehicle. My thinking is the car was designed to be powered from either location of the battery.


Old Battery Location


Front fuse Box


Rear Distro Box


And The reason I havn't sold this car, It truly is in beautiful condition, electrical gremlins aside:


Additionally while I was out there, I tested EVERY fuse back and front for continuousy, as well as the link, all passed. As old as some of the fuses look they all show 0.00 ohms.

I'm still not sure where to dig anymore in this car though, I feel as though I go out there and look at the same things expecting better results, but really I've covered all the obvious causes, or at-least I'd like to think I have.

My main goal is to fully trace those 2 cables from the link all the way to where ever they go, thus I should find where the voltage going in, drops out. Much Much Easier said then done I'm experiencing.
EDIT IN: Is it possible a faulty RM or GM module would restrict Voltage to the fuses? I would guess no, as logically the RM/GM come after fuses, just a passing thought.

To add to it all, I'm being pressured to sell this car, but I would really like to not sell it, as its a beautiful and super reliable e34. Though without wipers or windows, it simply wont be able to stay much longer. Also this is my daily driver, and it will be pouring rain for the next 3 days, should be a dangerous/interesting wiperless drive to work.  I apologize for the long posts, I'm a textbook over thinker

[DanOKC]

OK, I was wondering about the second battery option. so your car had it when it was new, but it must not be required if all was well before. i stumbled onto this info which shows three fusible links up front, one which is hidden inside 2 layers of heatshrink or plastic tubing, so you may have blown that one, if your car has it. also mentions f37 in back. i may not have the right etm’s if your car doesn’t have f37.

http://www.bmwe34.net/E34main/Maintenance/Electrical/Fusible_link.htm

another trick i do that i try to only do when desperate, if you have sharp probe tips on the dvm, you can puncture the insulation of a wire to check voltage in it. on a car if i did this, and it's under the hood, i would smear a small dab of silicone on the small hole to seal it after i was done.

sorry for no caps, my keyboard on this pc is flaking out.

[Gabs]

I've searched for 5 hours for any fusible links up front, and just tracing wires in general. Again I cant find where the power is lost to the rear box, but I know 100% that power is not getting to the rear box.

Though what I have figured out, is from the front fusible link one of those 2 cables actually went to the 2nd battery's positive post through the passenger side body. So the batteries worked in a series of sorts, I gather. The 2nd battery also acted as a secondary(redundant) source of power to the rear distribution box, or so the story of cables seems to lead me to believe.

 What I'm seeing after literally ripping every interior panel appart, is that the vehicle may have been able to have the battery in the rear seat or engine compartment or both. All the cables seem to junction at points in a redundant power supply type scenario, as if the chassis were built before they decided what model of vehicle it was going to be (ei. 525i,535i,etc). Hopefully that makes sense, you might have actually had to see it all with your own eyes to understand what I mean

Anyway, My next course of action is simple in concept, and safe as well(Edit In: Or So I Hope ). The 2nd cable that comes from the front fusible link down my passenger side, shows 12.41 volts. I am going to put a 50amp inline fuse on the end of that, and connect the other end to the cable that used to come off the 2nd battery's positive terminal and power the rear distribution box. So really its the same setup as OEM, just without the 2nd battery. I hope this is a solution that will let me work around the problem for the time being.

Worst case scenario, I fry a 50 amp fuse Off to the auto store I go.
Will report back in a couple hours.