Interior Lights Revisited (Long Post)

[saconnect]

This is a long post. Let me know if I'm wasting your time with this, or if it's helpful. It helped me just to write it up, but I'm not sure if this is the type of stuff you all want to see. I would post pictures, but this didn't work in the preview.

The car I'm working on is an e34, GK52300 built in 10/94, It's an Alpine White 1995 modle that's left hand drive made for the USA market I assume. It has 129,902 miles on it right now and runs and drives great dispite having an automatic transmission. Its more fun to drive in the hills (mountains) than my e39! I was going to part the car out or sell it, but after considering all of your advise from an earlier post, I decided to keep it and continue to use it to learn. It has offered, and is still offering let's say, some unique challenges in the electrical department, and I want to work through them one-by one.

These challenges include:

• Interior lights will not work in any mode at all no matter where the switches are placed.
• Trunk (boot) lights will not turn on when the trunk is opened.
• OBC will not light-up, but Dash computer display still works.
• The classic door lock problem. Lock w/key, locks pop-up, lock with key, locks stay down.
• Air Conditioner does not work because it seems to have a short somewhere in the electrical system.

Before I salviged the car, it had been used as a parts car. Many parts were missing or had been switched including radio, various switches, spare tire, SRS module, Jack, Keyless entry and security system modules, the check control module, (CCM) had been replaced with an older broken unit, door pannels and seats from 89 or older I'm guessing, door stops were gone, seat motors were missing, two seat belts had been taken, sunroof motor, light bulbs and sockets, hazzard switch, all tools were missing and the cruise control module. Dispite all of this, I was still able to drive the car home after replacing the battery and two headlight bulbs. I limped home TRANS-PROGRAM mode.

I've taken care of most all these missing items problems, replaced the seats and the door panel, and quite a few other small annoying things like a water pump, radiator, heater core, fan belts, fan viscus coupler, belt idler pullies, hoses and sensors, broken stabelizer bar, and over all, it's become a fairly presentable and nice car. I still don't have the SRS module that's under the rear seat, and it's still missing the security/keyless entry module. I'm afraid to install the SRS air-bag module since I'm afraid of explosions, and I haven't found the security module yet.

I've also been afraid to dig into the electronics of the car because it's a big unknown area, but after reading the other posts here, and figuring that I've nothing much to loose (I mean that the lights don't work now, and If I cannot find the problem, they still won't work), I decided to start digging into it and document what I find. I'm not a professional at all, and I'm only documenting what worked for me. This is not a recommended proceedure by any streach of the imagination and if you follow what I'm doing, you do so at your own risk. I'll tell you what I've done and where I get stuck...and hopefully someone can help me get unstuck when this happens and help us all. I would post pictures, but I don't know how.

Now that we know a little bit about what we're about to get into, I start by examining the ETM and identifying and tackeling the most simple of the electrical problems mentioned above...the Trunk lights will not come on. I'm working from the 1994 E34 Electronic Troubleshooting Manual. Pate number 6320.01 shows the complete circuit. I say that this should be the most simplest of the problems because according to the plate this circuit has only one fuse (F21) and does not go through any complicated computers or modules such as the General Module (GM) or the Relay Module (RM), so it should be pretty straight forward. I'm hoping that as an added bonus when tracking down this problem to find a bunch of broken wires in the same spot that wil magicly solve all the other problems too. I start troubleshooting by reading the diagram from the top down and checking each system component as I go.

The first item at the top of the page is Fuse number 21 (F21) in the front distribution box. So one of the first things I check the fuse to see that it is good using a continuity check with the handy multi meter. It's good. I can't just look at it and check it to see if it's burned out or the little wire inside is broken, because I've seen them where they look good, but have infact been broken. Since the fuse was good I checked to see that the connectors are not corroded. I checked both the male and female parts. If they are oxidized or dirty, I would clean them, but all is shiny and new looking. While I'm here, I checked that power is getting to the fuse by checking the voltage to ground on the battery side of the fuse. It was about 12 volts.

The next point on the map (schematic) following the fuse is the switch S81 or trunk lid switch. Now that is all the way in the back of the car in the trunk lid latch. To get to it you have to remove the grey covering from the bottom part of the trunk lid only. You could remove the whole cover, but it's not necessary. The switch is attached to the closing latching loop on the lid so that when it's closed, a slightly cone shaped pin pushes up from the bottom of the trunk up into the switch. From the diagram, you can see that if its open, or turned off, no power will flow into the circuit at all. This is exactly the symptom I'm experiencing because when I open the trunk, the lights do not turn on. Is the switch bad? I start by checking the continuity of the switch to see that when it turns on I have zero (0) resistance (ohms) between the leads of my multimeter. This is correct. And, when it is turned off, I have infinite resistance showing on my multimeter. This too is correct, and I can say without a doubt that this switch is working. I checked the contacts, and all are shiney and new looking. If the switch works, I should be getting power to the lights from the fuse, but since I'm not getting power, and the switch works, there should be a break in the line between the fuse and the switch...but it's not as easy as it looks on the diagram. It appears that there is only one (1) wire that runs completely from the front of the car's front fusebox to the switch. That's a long way, and a lot of wire going through a lot of hidden places. I

Next I check the obvious spot for trouble, the trunk hinge harness where it flexes. This is where most problems occur, and there are usually a few broken wires between where it comes out of the car and is attached to the trunk lid. I peal off the tape, and find all wires in good order. I was hoping for an easy fix, but not today.

Before I go digging into the various harnesses though, I'd like to make sure that the rest of the circuit is good. Since I have no anti-theft devices or explosive devices to worry about, and I know that the connection between the fuse and the switch is broken somewhere, I still need to verify the rest of the trunk lite circuit from the switch to ground, just to make double sure of the diagnosis. I decided to test the rest of the circuit by disconnecting the positive terminal of battery from the car, and applying +12 volts from the battery's + terminal directly to the other side of the switch that's not connected to the fuse. This worked, and the trunk lights lit up brightly. This means that all the rest of the circuit works perfectly upto and including the ground points X495 and X493. This also checks rest of the circuit including the bulbs and the grounds for proper functioning. It also confirms that there is no problem in the trunk hinge area since the power for each and every one of these lights comes directly from a splice X465 inside the car under the rear power distribution box and is routed through the trunk hinge. Which brings us to the next part of the diagram...the splice point just below the switch labled X465.

The electronic troubleshooting manual (ETM) shows that the next item in line is a splice point, X465, is under the rear distribution box. This splice point must also be good since all of the lights lit. Power runs from the switch to this splice, so, since the lights lit when power was applied to the wire going too the splice, I know that, as far as the trunk lights are concerned, there is only one wire that I need to run down, and this must be a long wire that comes directly from the fuse to the switch??...This means in any case that the broken wire does not go into the splice X465, and all is good from the switch on. Yeah, I don't have to tear out the carpet...yet, but I need to look for this wire.

Since all the wires in this circuit that feeds power into the circuit are Rot und Weiss (Red and White), I need now to start to look for a wire that's by itself that does not go into the splice. Now, I could start at the back around the rear power distribution box, but since the break is not in the obvious place, at the trunk hinge, and there are many many red and white wires running all over the place in and around the rear distribution box under the back seat of the car, I choose to start at the front of the car and follow the red and white wire from the fuse box or look for a red and white wire that's all by itself. That was the idea, but I get up to the front remove the panel under the steering wheel and start poking around under the dash, and find that there is also a whole lot of red and white wires up there too...now what?

Some how I need to sort out the red and white wires under the dash. I remember that the wires running to the interior lights are also red and white, so perhaps I could take a look at the diagram for the interior light circuit (6330.01) to help sort them out. Looking at this diagram, I see some red and white wires also coming from fuse F21 that leads to another splice point X435 before it branches out to the rest of the interior lights. So where is X435? X435 is somewhere in front of the right side of the rear seat...just outside the seat bottom metal wall...under the carpet I guess...so it looks like I will need to tear out the carpet anyway, but not yet.

Going back to the front of the car and looking closely at the harness, it's still not obvious which wire this is. To get a better look, I remove the right side kick panel, not an easy job as I thought, since you have to remove the lever that opens the hood to get it out, and I see that someone has been there before me. There is a jump between two pins of the yellow security relay that would presumably bypass the imobilization stuff, and the cruse control module is missing. At least it looks like they knew what they were doing, as it was nicely done, and the car still runs great. This might be an avenue to later investigate just to make sure this connection doesnt have any repercussions. Anyway back to the search.

Still baffeled by all the wires up in the front of the car, I start thinking about how F21 runs at least two circuits, what else does it run? If it does run something else, can these other circuits help me find the break? I find in the ETM, plate number 0670.3-11 that shows all the power distribution for F21. It sends power to the torch charger in the glove compartment (torch is also missing from the car), the trunk lid switch, and all interior lights. It also shows the X435 distribution point, but has two more new components that are not shown in the other diagrams. These are X14, and a splice X207. From the ETM component locator, X14 is a yellow 30 pin connector located under the LH kick pannel. According to the drawing, pin 16 of this 30 pin X14 connector should have power coming to it from F21. Splice X207 is shown as being on the fender side of the front distribution box before the X14 connector. I first reason that there are two branches off the X207 splice, the torch charger, and the wire going to the plug X14. If the connection is good at the X207 splice, I should be able to get a 12V power reading across the two prongs of the torch charger, and 12V at the X14 connection plug. Checking the torch charger, shows 12V. So we know we're good coming out of the X207 splice. I should also get 12 volts to ground at connector number X14 pin 16, if I can get the thing apart...there we go, and I'm surprised to find a good bit of corrosion in the conector, I must clean that, but I'm also surprised that I DO have 12 volts to ground at this connector at pin 16, and coming out of the other side of the connector when it's plugged in. Pin 16 was easy to find since it was the only red and white wire coming out of and into the plug. I should have checked that before I unplugged it....but the lights still don't come on, but I'm now closer to the break in the wire because I know that it has to be between X14 and X435. Looks like I'm going to be tearing out the carpet anyway.

I carefully pull back the carpet in that run's up the side of the seat near the area of the rear distribution box, and find that there is a black plastic protector over the harness...removing the protector by pulling out the plastic push pins I can see that there are a lot of splices in this area, but it's pretty easy to identify the red and white wires running into the splice. I have to remove the electrical tape that's holding them all together, and the shrink protector on the end of the splice. All looks good, but when I check voltage to ground, I get zero volts...at this point this means only that the wire coming from F21 to the splice is broken somewhere between F14 and the splice X435. While I'm there though, just for grins, I decide after taking another look at the diagram to connect splice X435 to +12 volts to see if things light up. According to the diagram this will bypass all the GM/RM stuff, and send the current directly to ground point X493, and I should see some lights. I know that this ground is good from troubleshooting the trunk lights, so I believe this might work, and in so doing check the rest of the circuit from F21 past X435. So I disconnect the positive terminal of the battery again, and jump the +12 volt side of the battery to splice X435, and the interior lights come on. Yeah! But this only means and verifies that I still have to find this one wire, and it does not check the power coming from the other two fuses that run the circuit, this is for another time, since I'm sticking to the F21 circuit right now. I reconnect the battery.
It's easy to identify which of the five wires comes from the connector X14. It's a little bit bigger than the other four. I start to check the connection from the splice to X14, but then while handeling it the whole X435 connection kinda breaks apart and falls off in my hands...the ends of each wire just below the splice were all a pretty tourquoise blue and broke off flush with the end of the wire insulation....I think I've found one problem...So I clean, splice and solder all the ends back together, and both the interior AND trunk lights work. Yeah, success! Two birds with one stone?

So at this point, I've been able to get the trunk lights to work automatically when the trunk is opened, and the interior lights to work in manual mode. The lights also work now when I pull up on the drivers door handle. They do not work when I open the doors. This is a little more complicated since this circuit goes through the GM/RM and depends on input from the door switches, relay's, timers, and other more difficult factors. I'm going to stop here for now, and post this step and pick-up on the lights coming on when the door opens circuit on my next post to this thread.

[Qube]

Holy moley! I tried to read through it, but stopped less than halfway. Your post, while comprehensive, is too blocked! Split the text even more by spacing out the paragraphs (double space between perhaps)? Try it. Go ahead and edit/add another line break or two between paragraphs. It will help to break up the sea of text. Maybe there are others with more patience to read thoroughly, but in a nutshell, your problems are:

Interior lights will not work in any mode at all no matter where the switches are placed.
Trunk (boot) lights will not turn on when the trunk is opened.
OBC will not light-up, but Dash computer display still works.
The classic door lock problem. Lock w/key, locks pop-up, lock with key, locks stay down.
Air Conditioner does not work because it seems to have a short somewhere in the electrical system.

[saconnect]

[quote=Qube]Holy moley! I tried to read through it, but stopped less than halfway....

Thanks Qube, I removed a lot of stuff and sumarized up front so that if you want to know more, it's there, but the important stuff is in the first few paragraphs.

After reading many many posts on this forum, which is the best BTW, the two biggist frustrations I have are that the person with the problem gives up and takes it to their indy, or stealer, and drops the thread, or that I'm following along with an electrical problem and everyone magically go into a chat room, telephone or other means of personal communication and POOF, all is solved. There's almost always a little explaination at the end, but the middle always seems to be missing in the majority of the threads...Dispite this this forum provides the BEST information there is! Here I go rambling again.....

[The Bigfella]

Good sleuthing - keep at it.

[saconnect]

This afternoon I didn't have much time, so I went back to the same area where I found the broken wire and started checking the other connectors by pulling on each of the wires in all the splices. I Found seven total that crumbled in my hand...all of the little wires. The big (larger diameter) ones seemed fine So I left the big ones alone, and just splice the small ones. Should I resplice the big ones too for good measure?

If you remember too the OBC was not lighting up. I pulled it out and found that it had no bulbs in the display. Since I don't have any more bulbs, but I have another e34 with a working OBC, I swapped them. The swapped computer worked!

So I'll need another one of these...or some bulbs. Should I get these from the dealer,or go to realoem and get the part number and order them from Pelican parts? It's probibly a good idea to swap the bulbs from the working OBC first, right? I didn't think about this earlier...just writing in this forum is inspiring!

So I only have three items left to worry about, and that is the A/C stuff, and even though I fixed a lot of splices, the lights still don't come on when I open the doors, and the door locks still pop-up from time to time. I'll see what I can get done after work tomorrow starting with the door open lights.

[saconnect]

[quote=Qube]Holy moley! I tried to read through it, but stopped less than halfway.
[quote]

I spent a couple of hours editing the hell out of this, and cut out about 1/2, submitted the reply, and no changes...maybe I'll try again. Thanks again for the advise.

[Paul in NZ]

Hey I read it ALL!.I agree that a lot of times there is a big dicussion but often no real conclusion is reached.I admire your determination and clear description of the problems you have found and your reasoning to get there.
It sounds like you have an early GM,because the later GMs did not have the relock feature.Either that or there is a short in the door or wring going to the door.It seems strange to me that the door handle activates the lights but the doors dont.You know the witches for the lights are small switches built into the door latches themselves?
What do you think is the cause of the strange corrosion /degradation of he wiring?
Keep it up it already sounds you have made huge strides with an iconc car....E34 touring.They ae very very rare here.

[saconnect]

It sounds like you have an early GM,because the later GMs did not have the relock feature.Either that or there is a short in the door or wring going to the door.It seems strange to me that the door handle activates the lights but the doors dont.

The number on the GM ends in 41. It's the same one I have in my 94 which was built sometime in Mid 93. Realoem calls for one with the same number ending in 42. That's probibly not close enough. I'll be on the lookout for a 42, meanwhile, do you think that this is enough of a difference in GM's to cause problems?

What do you think is the cause of the strange corrosion /degradation of he wiring?

That is a strange one...There is no rust at all on the car nor under the carpets, and the electrical tape wrapping the splices it was the original. The carpets seem to be pretty water proof, and there is not evidence of staining from a beverage spill. Even so, It has to have gotten wet some time, but it's very dry now. Speculation could keep me going for another hour, but my best guess was a large glass of water, open windows during a deluge?

Keep it up it already sounds you have made huge strides with an iconc car....E34 touring.They ae very very rare here

.

The're not too common here either. The touring is my favorite...more so than the X3/5 and the newer e39's It was in perfect condition until yesterday when the blower motor stopped...looks like I'll be looking at swords and blower motors tonight instead of tracing wires on the sedan..

I'm going to add the driver's door hinge to the list of things to check out.

[bbig119]

Great post! --- Have you considered publishers? Maybe a trilogy? j/k.

Reading this reminds me how lucky I am not to have major electrical gremlins(yet), but also is a good inspiration for anyone who does have them. I'm sorry I can't help you out much as I haven't gone digging in the electrical system all that much, but I'll be sure to follow your progess as you post it.

I too also echo your displeasure of unfinished threads, but its so easy to feel overwhelmed with a problem in the beginning, get some help and tackle it-- usually with a laundry list of other problems waiting at the other end. An equal problem is confusing/conflicting information when searching for information that differs between models, and build years. ie sword/blower resistor pack.

[saconnect]

I too also echo your displeasure of unfinished threads, ...

It's not a displeasure really, but more of a frustration...just when you get to the good part ...;-)