1985 635 CSi - Electrical problems

[jasonseck]

hi everyone - i'm the proud new owner of an 85 635 CSi.

i'm having some crazy electrical problems and i wonder if anyone has advice. here's the breakdown, with a question at the end:

-sometimes i turn on the car and the radio clock and stations are reset. the o n board computer usually flashes UHR (which is german for time, right?)

-sometimes when driving, i will notice one of my gauges 'blip' for a second. it's not a spike like they max out. after the blip, usually the OBC has reset. sometimes it say uuYYjjDDtt, sometimes it says UHR. sometimes it flashed the PPPPPs. the radio keeps all of its settings.

-recently, the OBC had one of its reset freakouts, and the display simply said CODE. in this case i was unable to start the car. the car would crank but would not turn over. i was able to solve the problem by removing the connection to the battery, waiting for 1 minute, and reconnecting. the OBC then flashed UHR and the car started. this has happened twice.

-when i'm driving and the instrument panel freaks out, the left side mirror sometimes rotates all the way in. this happens regardless of if the mirror switch is set to control the left or right mirror.

i don't yet have a manual, though i plan to get one.

here's my question. i want to completely get rid of the OBC. some of the symptoms i'm having make me think that the OBC is deeply tied to the car and that i can't get rid of it.

my plan is the replace the OBC and stereo with a mini ITX computer with wifi, bluetooth, and a touchscreen.

i would greatly appreciate any advice on removing the OBC, and on the electrical system in general.

thanks for your time!
jason

[Alex E24 E30]

First off: Welcome! Congrats on your new purchase!

On to your questions:
When things go berserk, my first thought is to check all of the body ground points. It's the easiest and cheapest to take care of, and in my case, it solved my electrical quirks.

For the body ground locations, download your Electrical Troubleshooting Manual here.
This is an invaluable resource.

I'd start with cleaning the grounds and see what issues that solves. This manual will tell you everything electrical that you need to know. I can tell you that the CODE that flashed is the vehicle's security setting. If the code is set, the car cannot be started. There is a way to reset the code so that you wouldn't have to disconnect the battery, but I'm not familiar with that procedure. No doubt, this will get answered shortly.

I like the OBC, personally, but with the issues you're having, I can understand the frustrations. My car's gauges would blip anytime I hit the brakes, window buttons, flashers, and wiper blades. I also had dangerously low headlamp lighting. All of these were fixed by cleaning off the body ground points. I used a wire wheel on a dremel and sandpaper.


Alex

[Alex E24 E30]

Oh...and when you get your post count up to 20, let's seem some pics of the new ride!


Alex

[jasonseck]

Alex - Thanks for the good advice and the link.

The Electrical Troubleshooting Manual is exactly what i need to figure this one out. If i can get the OBC to be less flakey, i probably will keep it.

I've had this car for about 2 months, and i love it. it's almost perfect in terms of road worthiness (after a little repair work). i can't wait to get the interior of the car looking and acting great.

thanks again.
jason

[Alex E24 E30]

No problem. Keep us posted!

Alex

[CW6er]

Welcome !

Some things you will need:

There are no aftermarket repair manuals for the Six, but it shares the same engine, drivetrain, suspension and many systems with the 5-Series so the Bentley BMW 5-Series '82 to '88 (Green cover, $38 at Amazon.com) Manual works very well. The "Driveablity" and the fuel injection sections alone are worth the price.
[ame]http://www.amazon.com/BMW-5-Service-Manual-1982-1988/dp/0837603188/ref=sr_1_3/105-9530707-1070056?ie=UTF8&s=books&qid=1181794459&sr=8-3[/ame]

The other is an ETM (Electrical Troubleshooting Manual). Here is a free download of a PDF file for your year ETM:
http://wedophones.com/BMWManualsLead.htm

There is also an online ETM for an '85. It has much clearer component location pictures then the downloaded ETM's:
http://www.stormpages.com/countchocula1/bmw/etm002.htm
(The component location listings at the end of the ETM are invaluable as you find your way around the new car)

A gold mine of articles and how to's; BigCoupeGroup Tech Library : (different then BigCoup)
http://www.normgrills.net/bcg/

And last but not least, there are 3 online parts catalogs:

RealOEM.com, the original and I still find it the fastest to navigate if you are still on dialup:
http://www.realoem.com/bmw/select.do...ies=E24&arch=1

BMWFans, more graphic, so slower for dialup, but if you click on the part number in the right hand column, it will show you all of the other cars the part was used on. Very handy for hunting at the salvage yard:
http://bmwfans.info/original/E24/Cou/

Maximillian Importing, they will sell you the part, but the price isn't much better then the dealer:
http://www.bmwmobiletradition-online.com/bmw/


For parts, the lowest prices I've found on the net:

http://www.Stevehaygood.com/
http://www.AutoHausAZ.com

Below are good references, and sometimes they have things the others don't, The prices aren't the lowest but sometimes they surprise, so I check all 4 when looking for parts:

http://www.Pelicanparts.com
http://www.BavAuto.com (Great Catalog, order it, it's free)

[HayekFan]

All of these were fixed by cleaning off the body ground points.

Are these ground points the ones in the engine bay where the ground straps attach, or are there others?

[Alex E24 E30]

IIRC, the main body ground that's on the inside left fender in the vicinity of the power distribution box (approximate location) was the biggest corrosion spot that was on my car.

For reference: body ground points = many wires (brown in color, I believe) meeting at one location. I think they are held down by a bolt or large screw. Different than the ground straps, but those would be a good thing to clean as well. It couldn't hurt anything.

I think there's another main body ground under the hood as well.
There's also another main body ground point under the dash, but I don't remember if it needed tending on my car. I wanna say that there's also another under the rear seat, but I could be mistaken.



Alex

[HayekFan]

IIRC, the main body ground that's on the inside left fender in the vicinity of the power distribution box (approximate location) was the biggest corrosion spot that was on my car.

Okay, I'll have to check that out on mine. I don't have any particular electrical problems but it sounds like the kind of thing that's worth looking at.

For reference: body ground points = many wires (brown in color, I believe) meeting at one location.

Yep, now that I think about it, I have noticed brown wires grouped together here and there.

Thanks!

[CW6er]

Look in the back of your ETM, they list the connectors and grounds and where to find them.

[jasonseck]

hey CW6er, can you repost the link for the online version of the ETM, please? it appears to have been truncated.

thanks!
jason

[CW6er]

hey CW6er, can you repost the link for the online version of the ETM, please? it appears to have been truncated.

thanks!
jason

Aha, Yes. Bimmerforums sometimes truncates the displayed link when it is too long but leaves the full link in the HTML code underneath. The problem is that when you cut and past from a previous post like I did, you only get the truncated display and not the full link!

Several of the links were broken so I edited the post above and fixed them all.

Hope this helps

[jasonseck]

an update on the weird problems i was having...

i went through and cleaned all of the ground points with a dremel. the headlights got brighter, the OBC started working correctly, and the power mirror stopped moving on its own.

everything was great until i had to slam on the brakes hard today(brooklyn traffic) and the power mirror suddenly moved on its own, again.

it remained stuck wanting to turn all the way in until i powered the vehicle off and then on again.

[detroit635csi]

LIES!!
6ers DONT have electrical issues

[CW6er]

......... and the power mirror suddenly moved on its own, again.

The mirror problem is obvious, you lost track of time lusting after Phoebe Cates and fed Gizmo after midnight again! and now the gremlins are in the mirror!

What was bugging me was, how could the mirror get power to seemingly come on all by it's self?? But if you look at page 153 of the ETM, you can that the center contact of the Mirror Control Switch is hot all of the time with the key on, and passes power to the mirror so that the mirror heater can work. This also exposes one side of the motor to voltage and all that is left is to ground the other side for the motor to come on.

Flip the Mirror Selector Switch to the other mirror and see it the problem starts in the other mirror. If it does, the problem is in the Mirror Control Switch. If not than the problem may be in the wiring, or the mirror internally shorting to ground.

I just noticed one small problem with my theory, lets see who can spot it.

[jasonseck]

quoting...
Flip the Mirror Selector Switch to the other mirror and see it the problem starts in the other mirror. If it does, the problem is in the Mirror Control Switch. If not than the problem may be in the wiring, or the mirror internally shorting to ground...
/quoting...


i pulled the mirror switch out, and the problem went away. i took the switch apart and cleaned it, hoping to solve the problem. put the switch back in and it went goofy again, right away.

what i've now figured out is that it is NOT the switch, it's the wiring somewhere between the switch and where it enters the car. the switch is making something always hot, and the short happens when i open and close the door, or somehow otherwise stress the connection (i.e. slamming on the brakes.)

too bad... i wish it was the switch.

[Romney88635]

There is also a 635 / M6 shop manual available as a free download here http://www.megaupload.com/?d=C09JK5AU

Probably not too useful for the current problem, but it will come in handy!
(300+ meg upload BTW)

[Bert Poliakoff]

quoting...
Flip the Mirror Selector Switch to the other mirror and see it the problem starts in the other mirror. If it does, the problem is in the Mirror Control Switch. If not than the problem may be in the wiring, or the mirror internally shorting to ground...
/quoting...


i pulled the mirror switch out, and the problem went away. i took the switch apart and cleaned it, hoping to solve the problem. put the switch back in and it went goofy again, right away.

what i've now figured out is that it is NOT the switch, it's the wiring somewhere between the switch and where it enters the car. the switch is making something always hot, and the short happens when i open and close the door, or somehow otherwise stress the connection (i.e. slamming on the brakes.)

too bad... i wish it was the switch.

Good chance the wiring is frayed where it goes through the door. On my car there was three or four totally frayed/broken wires in the harness that does the mirrors and door locks. Spliced them, covered thew splices with shrink tube and then covered the whole harness with two layers of shrink tubing. This area is prone to trouble because of the flexing of the wires when the doors are opened and closed

[rod635]

Hi everyone just joined the forum and this is my first post.
I am currently in the process of purchasing a 1989 635 CSI that has been lying up for some time. The electric windows on one side and central locking are not working, the windscreen wipers move extremely slow and the headlights only seem to work when the stalk is pulled back not when they are turned on. We can't see any blown fuses, and ideas or is this a job for an auto electrician?

[e24mpwr]

Hi everyone just joined the forum and this is my first post.
I am currently in the process of purchasing a 1989 635 CSI that has been lying up for some time. The electric windows on one side and central locking are not working, the windscreen wipers move extremely slow and the headlights only seem to work when the stalk is pulled back not when they are turned on. We can't see any blown fuses, and ideas or is this a job for an auto electrician?

Welcome!

I'd guess there's more than one thing going on - I'd take it to a mechanic unless you've got some expertise in this area. I can do nuts and bolts kind of stuff, but I leave electrical, etc. to folks who know what they're doing.

[ldk]

Get the Electrical Troubleshooting Manual here: http://wedophones.com/Manuals/BMW/

Your issues shouldn't be too tough to track down.