youngbimmer's recent tragic loss to fire reminds me to repeat my Fire Warning to all E32 owners!
Our cars have an un-fused circuit, which can, and does, cause engine wire harness melting and possibly fires!
My 1992 735iL had suffered this harness melting failure before I bought the car, and I had to repair the repair work.
It is the WHT-YEL (WS/GE) Diagnostic Datalink RXD wire, which is jumpered to 12V by a link connecting Pins 14 - 15 inside the black Diagnostic cap D100 (X6002) in the engine bay.
BUT THIS LINK IS NOT FUSED! So a short of the WHT-YEL wire to GND anywhere in the car will cause the wire loom to melt! This likely caused youngbimmer's airbag to inflate, and his starter motor to run with no key in the ignition. It was a "short-fest" inside the wire loom!
See Pg 0680-23 and 0680-09 to 14.
The quick fix is to remove the D100 cap and leave it off! The permanent fix is to cut the Pin 14-15 shorting link inside the D100 cap, and solder a 100 ohm resistor across the cut.
Last edited by E32FAN; 06-21-2018 at 11:11 PM.
Question: would it also help to install a inline fuse in the WHT-YEL (WS/GE) Diagnostic Datalink RXD wire? If so, how many amps is recommendable and where (location) recommendable?
Shogun tricks and tips for the E32 series are HERE!
Was just going to ask the same question. Do e34’s have this problem? I know they have a lot of similarities, the only thing I remember on them is the fuse box fires
Me E30 87/ 325i + F25 12/ M-Sport + E32 94/ 740i
G/F’s E34 92/ 525iT + F48 18/ X1
Looks like the E34 is same, see page 0670.6-10 and -11
Pin 14, terminal 30 , VOLTAGE: HOT AT ALL TIMES
Pin 15, RXD, WS/GE
http://shark.armchair.mb.ca/~dave/BMW/e34/e34_93.pdf
questions:
Is Pin14 fused by the fusible link near the battery?
what is the actual pupose for: ... jumpered to 12V by a link connecting Pins 14 - 15 inside the black Diagnostic cap D100 (X6002) ? Because you say we could remove the cap completely as a quick fix.
Last edited by shogun; 06-22-2018 at 11:24 AM.
Shogun tricks and tips for the E32 series are HERE!
Yes, pin 14 is fused by a fusible link, but it is just a #20 AWG (0.5 sq mm) conductor so it will burn up long before the link opens.
I believe that the D100 Pin 14-15 jumper is intended to keep the RxD line quiet when not in use for Diagnostics. I suspect that we could safely cut off the pin 15 in the D100 cap and let the WHT/YEL wire float. I will make some tests and report back.
Yes, a fuse should have been designed in. A 1 Amp fuse would protect it. Notice splice X182 in E34 = splice X182 & X6864 in E32 M30, X6863 in M70. These splices join a large number of wires! The fuse would have to be installed in the D100 connector boot. But what if it blows? How to install it? A 100 ohm resistor in the cap acts to limit the fault current to 12/100 = 0.12 Amps, so the resistor acts as the "fuse" in effect.
The problem is that the RxD wire connects to every module in the car! So a short to GND on any of these WHT/YEL wires will burn up the harness along the path. And the molten copper might melt into the airbag or starter wires.
Anyone have a pic of this connector? Don’t want my daily baby burnin down!! Oh wait do we mean the big round twisty cap thingy? Yeah I feel like you could just fuse the hot lead before the cap right?
Wasn’t there a fire possibility on the passenger side under the rear seat?
Last edited by 6erWEBB; 06-22-2018 at 09:54 PM.
It is the 20-pin diagnosis plug with D100 cap. Left side of the engine bay, there are on the 750 3 big black connectors between Pentosin container and water valve. These http://bmwe32.masscom.net/sean750/sp...minalAway2.jpg
On the 750 the one on the left side is the diagnosis port D100. Middle is X21 connector 20 pins, right side is X20 connector 20 pins.
see pics in section 7100 component location views http://shark.armchair.mb.ca/~dave/BMW/e32/e32_88.pdf
One hint from my own experience, found that out a few years ago: these 3 connectors are clipped into a metal bracket #3 http://www.realoem.com/bmw/enUS/show...diagId=12_0334
this bracket is only held by 2 plastic nuts. When these plastic nuts are not good anymore and do no hold the bracket tight, the bracket starts to vibrate and the cable looms coming out at the bottom of these 3 connectors touch metal below the bracket, that causes damage to the original wire loom protection. In case of my car one of the outer wire loom protection tubes was cpl. damaged, but luckily not the single wires inside. I repaired the protection with plastic spiral wire looms and used 2 new plastic nuts to tighten the bracket.
If I would not have found this damage early enough,.....
But we also should not panic. There are so many E32 still running for abt. 30 years now and only a few one had this problem, that that wire loom got damaged. Wire loom damage can happen on many places, and even if there is a fuse, sometimes a fuse does not help and the fuse box melts with the wires.
Rear seat fire is a different case, that is usually the fuse for the rear window defogger https://www.bimmerforums.com/forum/s...ear-seat-pics&
Comment by Johan: Problem : At some point the fusebox caught fire. Probably due to corroded contacts. That's exactly why I always replace the fuses and clean the contacts of the fuse holders in an older car.
Here the thread where younbimmer's car caught fire https://www.bimmerforums.com/forum/s...ctory-5spd-735
Last edited by shogun; 06-28-2018 at 09:09 AM.
Shogun tricks and tips for the E32 series are HERE!
Many thanks to E32FAN for enlightening us. I’ll be sure to do this mod ASAP to ensure this doesn’t happen to my baby - thx!
Experiment: Driving with D100 open
Let's have as many as possible cars drive with their D100 cap removed from the diagnosis port, and collect the field reports from these trials for E32Fan. If a module becomes confused, the car may go to limp mode until re-started with the D100 cap back in place. But this may never happen. This is evidence-based, experience-driven.
Shogun tricks and tips for the E32 series are HERE!
Tried that. After starting the engine, the EML light came on, but no messages were displayed. When I couldn't get up the ramp to get our of my basement garage, it became clear that the car isn't running properly. After putting the cap back on, the EML light still came on. In the end I took the cap off, turned the ignition on and off, then put the cap back on, and everything was back to normal.
Update (2018-07-23):
I've had the issue with the EML light three times now. This is probably (hopefully) the usual problem with sticky throttle bodies. It was just coincidence that it first happened when I was experimenting with the diagnostic cap.
Last edited by kce1900; 07-23-2018 at 09:49 PM.
I took the cap off my car Saturday and drove approx 25km. No errors or issues over multiple trips involving many shutdowns/start ups.
Test result 11/88 750, Motronic M1.2: engine cold, used Peake tester and checked, both banks zero faults. Then took off the diagnosis cap and started the engine, EML light went on and off as usual, engine had full power during test drive, no EML light came on during test drive w/o the cap. Then checked again with the Peake tester, same result, zero faults in the system.
Shogun tricks and tips for the E32 series are HERE!
There is a great Auto Fire Extinguisher made in Germany.......Only thing it does not ship here and I can't find it anywhere on this side of the pond. Very nice.....Comes in a bag that closes as well as a foot well mountain bracket. Wish I could find another way to get my hands on a couple. I take it back.....for 35 Euros they will ship. I think I'll treat myself to one of these.
Last edited by CroughtonE32; 06-27-2018 at 09:44 PM.
1990 735I (Auto) E32 Feb 1990 to Present
1996 Z3 Roadster (5 Speed) E36/7 Jan 1999 to Dec 1999
1983 733I (5 Speed) E23 April 1983 to Feb 1990
https://www.youtube.com/watch?v=2d4tHoHGaJo
https://1drv.ms/v/s!Av20xCMMocSsyEpl...h_oOk?e=ekIcAT
Modification instructions by E32Fan
Shogun tricks and tips for the E32 series are HERE!
Thanks for that info, E32FAN, you said the short occured in the seat module. Are you saying that your fix won't work in the end? Or is only a partial fix to a bigger problem we may face? For now I think i'll leave the cap off because I do not want to see my car burn down, maybe this weekend I will do the cap modification. Worried about the blower fan as well, but not sure how to prevent that from causing issues.
BMW 7er Website www.7er.com
1989 BMW 735i Schwarz (sadly, sold) // 1989 BMW 750iL Cirrusblau Metallic // 1998 BMW 740iL Oxfordgrün Metallic // 2000 M5 Carbon Schwarz ///
My Memory Seat module developed a fault that shorted WHT-YEL to GND. With the fused Diagnostic Cap in place, this would blow just the fuse wire and the repair would be to disconnect / replace the seat controller and solder in a new fuse link. Damage contained.
The Blower Motor fuse is F19, 30 Amp. You might change it to 20 A for safety, and not run the fan at top speed. Just a suggestion.
Chioliny from the German 7-forum took E32fan's idea a step further. Instead of using a piece of wire strand he soldered the metal strip from a 5A "torpedo" fuse across pins 14 and 15. In addition, he soldered an LED with a series resistor in parallel to the fuse. The LED will illuminate only after the fuse blows. He glued the LED into a hole drilled into the cap so it is visible from the outside, and he managed to reinstall the PCB using some kind of plastic solder.
Now both versions on the shogun site under upgrades>>
Fusing the diagnostic plug
Preventing short circuit fires
two versions, one with LED
Shogun tricks and tips for the E32 series are HERE!
This plug is supposed to be identical on many BMW models, but E32Fan and Chioliny have different plugs on their respective 735: one has five pins, the other has four. Is this difference significant?
Last edited by kce1900; 06-30-2018 at 01:36 AM.
Based on realoem the cover was the same for all E32 M30, M60, M70
12521724690 Cover, diagnostics plug From: 07/10/1989 - installed on all E32 and more http://www.realoem.com/bmw/enUS/part...&q=12521724690
Supersedes: 12521711220 (06/01/1986 — 03/01/1996)
Could be that the older and newer version caps look different?
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Page 1360-08 shows Pin 18 GN/BL also in DME 1.3 for the M30 engine.
So some cars Ground pin 18 and others do not, and that explains the 5th pin.
However we only need to fuse pin 15.
Nice to know why my harness fried several years ago. I had to order on from the USA to get it back on the road. I think part of the problem is the tape coming unraveled due to age and exposing the harness to rubbing.
One hint from my own experience, found that out a few years ago: these 3 connectors are clipped into a metal bracket #3 https://www.realoem.com/bmw/enUS/sho...diagId=12_0334
this bracket is only held by 2 plastic nuts. When these plastic nuts are not good anymore and do no hold the bracket tight, the bracket starts to vibrate and the cable looms coming out at the bottom of these 3 connectors touch metal below the bracket, that causes damage to the original wire loom protection. In case of my car one of the outer wire loom protection tubes was cpl. damaged, but luckily not the single wires inside. I repaired the protection with plastic spiral wire looms and used 2 new plastic nuts to tighten the bracket. If I would not have found this damage early enough,.....
In addition I added more flexible spiral wire wrap to other old wire looms, for example the ones for the MAFs, also there I detected broken wires caused by the old hard original outer sheath. I replaced a lot inside engine bay, the old harnesses are stone hard and when they break they cut into the single wires inside. So the old, hardened outer plastic sheath I removed, used new tape and in addition on some critical points added plastic spiral wire looms.
Last edited by shogun; 07-02-2018 at 04:52 PM.
Shogun tricks and tips for the E32 series are HERE!
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