98' 740IL Electrical Problems
larryrussell
12-14-2004, 11:54 AM
I have a 98' 740IL which has many electrical problems which have shown-up only to have them seemingly fix themselves. The problems include:
------------------------------------------------------------------
- The radio quits working.
- The OBC monitor goes blank / the dash display of information by pressing the button on the end of turn signal displays proper information.
It suddenly starts working after a few/many days.
------------------------------------------------------------------
- The Check Brake Light comes on.
It will suddenly goes off after a few/many days.
-------------------------------------------------------------------
- Check Engine light comes on.
It will suddenly goes off after a few/many days.
-------------------------------------------------------------------
- Turn indicators fail to display but the lamps flash as usual.
- Highbeams are not indicated on dash display, but headlights work as usual.
They suddenly work properly after a few/many days.
------------------------------------------------------------------
What could be the problem?
Larry
------------------------------------------------------------------
- The radio quits working.
- The OBC monitor goes blank / the dash display of information by pressing the button on the end of turn signal displays proper information.
It suddenly starts working after a few/many days.
------------------------------------------------------------------
- The Check Brake Light comes on.
It will suddenly goes off after a few/many days.
-------------------------------------------------------------------
- Check Engine light comes on.
It will suddenly goes off after a few/many days.
-------------------------------------------------------------------
- Turn indicators fail to display but the lamps flash as usual.
- Highbeams are not indicated on dash display, but headlights work as usual.
They suddenly work properly after a few/many days.
------------------------------------------------------------------
What could be the problem?
Larry
jcarey
12-16-2004, 11:05 AM
I have a 98' 740IL which has many electrical problems which have shown-up only to have them seemingly fix themselves. The problems include:
------------------------------------------------------------------
- The radio quits working. " There is a know issues with the Radio intermittently gogin out. Replacement is required with a newer updated model."
- The OBC monitor goes blank / the dash display of information by pressing the button on the end of turn signal displays proper information.
It suddenly starts working after a few/many days. "This is a function of the Instrument Cluster, which may be going bad, or the dot matrix display is failing but there is no individualreplacement for it, only a replacement cluster"
------------------------------------------------------------------
- The Check Brake Light comes on.
It will suddenly goes off after a few/many days. Make sure you look at the car from the outside when someone else is hitting the brake pedal. It is easy to overlook the third rear light. This system is usually good at indicating a bad bulb somehwere."
-------------------------------------------------------------------
- Check Engine light comes on.
It will suddenly goes off after a few/many days. Can be many things including your gas cap that will cause this light to come on. Get the car's error code memory read by a tech to find out what faults are creating this light to come on. If theya re all the same one, then you have a bad component that requires rpelacement. IF theya re all over the place, then there could eb a contorl module failing"
-------------------------------------------------------------------
- Turn indicators fail to display but the lamps flash as usual.
- Highbeams are not indicated on dash display, but headlights work as usual.
They suddenly work properly after a few/many days. "Again this is a finction of the Instrument Cluster and it may be failing or have a bad connection. Can you remove it and verify the connections are secure?"
------------------------------------------------------------------
Larry
Good luck,
happy holidays,
------------------------------------------------------------------
- The radio quits working. " There is a know issues with the Radio intermittently gogin out. Replacement is required with a newer updated model."
- The OBC monitor goes blank / the dash display of information by pressing the button on the end of turn signal displays proper information.
It suddenly starts working after a few/many days. "This is a function of the Instrument Cluster, which may be going bad, or the dot matrix display is failing but there is no individualreplacement for it, only a replacement cluster"
------------------------------------------------------------------
- The Check Brake Light comes on.
It will suddenly goes off after a few/many days. Make sure you look at the car from the outside when someone else is hitting the brake pedal. It is easy to overlook the third rear light. This system is usually good at indicating a bad bulb somehwere."
-------------------------------------------------------------------
- Check Engine light comes on.
It will suddenly goes off after a few/many days. Can be many things including your gas cap that will cause this light to come on. Get the car's error code memory read by a tech to find out what faults are creating this light to come on. If theya re all the same one, then you have a bad component that requires rpelacement. IF theya re all over the place, then there could eb a contorl module failing"
-------------------------------------------------------------------
- Turn indicators fail to display but the lamps flash as usual.
- Highbeams are not indicated on dash display, but headlights work as usual.
They suddenly work properly after a few/many days. "Again this is a finction of the Instrument Cluster and it may be failing or have a bad connection. Can you remove it and verify the connections are secure?"
------------------------------------------------------------------
Larry
Good luck,
happy holidays,
libertylover
12-19-2004, 07:28 AM
Just to add a few ideas to good advice that John provided:
Some of the dashboard wierdness may be caused by failed capacitors on the dashboard circuit board. To get to it you have to remove the steering wheel which means you have to remove the airbag, so don't try it without very good instuctions.
On the earlier E32 models, like mine, the Light Control Module (LKM) has infamously bad solder joints at the relays which can cause some really strange things. I think this module is located under the hood or behind one of the footwell panels.
In addition to this one, another good site is www.roadfly.org, which has a different forum for each chassis. I've surfed the E38 forum and most of the owners there pay to have their cars fixed, while on the E32 most owners fix problems themselves since they/we tend to be less wealthy. Look at the E38 forum first but also remember the E32 forum. Also, the search engine for that site seems to be forum-specific. Good luck.
Some of the dashboard wierdness may be caused by failed capacitors on the dashboard circuit board. To get to it you have to remove the steering wheel which means you have to remove the airbag, so don't try it without very good instuctions.
On the earlier E32 models, like mine, the Light Control Module (LKM) has infamously bad solder joints at the relays which can cause some really strange things. I think this module is located under the hood or behind one of the footwell panels.
In addition to this one, another good site is www.roadfly.org, which has a different forum for each chassis. I've surfed the E38 forum and most of the owners there pay to have their cars fixed, while on the E32 most owners fix problems themselves since they/we tend to be less wealthy. Look at the E38 forum first but also remember the E32 forum. Also, the search engine for that site seems to be forum-specific. Good luck.
marki
12-24-2004, 10:20 AM
I "think" but don't know for certain that these cars seem to be a pain in the ass with the electronics. This was one of the first to make the transition from electo-mechanical to electronic and it seems to me that they just didn't quite get it 'right'!! Just normal 'wear and tear' is enough to render the electronics "flaky" and produce intermittent problems w/ the various systems. I had a dealer tell me an interior courtesy lamp was "broken" yesterday and he tried to sell me a new part at a cost of some $128 plus the bulb for it. By literally re-bending one of the contacts back into proper position, and replacing the unit in the headliner (rear passenger seat courtesy lamp) it functioned perfectly and probably will do so for years to come. How it got "loose" is a mystery. The car's never been hit - so it's anybody's guess what happened. However, the "fix" was rebending the metal contact to fit the bulb and make contact again. Much cheaper than a $128 dollar part plus installation.
My 98 740i (which I love!) has LED's burned out on the CD/Radio display and the burned out lights (if they're linked to a feature or function) seems to also kill that feature or function. I cannot select disk 3 on the CD Player nor can I get to my FM Preset on Button 3. Seemingly because the display light above this button is out. Or maybe the lamp is out because of a contact problem at the board level. Who knows?
I'm logged on today looking for someone who does board level repairs and/or exchanges on these very costly electronic parts and control panels. The dealer prices for replacement/exchange start in the low four figures. While I love this car, I'm not going to pump another two grand into it just to get the Radio to function completely - or not if there's another choice anyway.
BTW: IF ANYONE has a company who will do board level repair/replacement on the Climate Control Heads / Radio/CD/Tape unit / Dash Displays / PLEASE LET ME KNOW. It's obviously cheaper to get these replaced at ONE time rather than incurring three or four different labor charges for tearing into the dash and putting it back together with the replacement parts.
Thanks
Marki
I have a 98' 740IL which has many electrical problems which have shown-up only to have them seemingly fix themselves. The problems include:
------------------------------------------------------------------
- The radio quits working.
- The OBC monitor goes blank / the dash display of information by pressing the button on the end of turn signal displays proper information.
It suddenly starts working after a few/many days.
------------------------------------------------------------------
- The Check Brake Light comes on.
It will suddenly goes off after a few/many days.
-------------------------------------------------------------------
- Check Engine light comes on.
It will suddenly goes off after a few/many days.
-------------------------------------------------------------------
- Turn indicators fail to display but the lamps flash as usual.
- Highbeams are not indicated on dash display, but headlights work as usual.
They suddenly work properly after a few/many days.
------------------------------------------------------------------
What could be the problem?
Larry
My 98 740i (which I love!) has LED's burned out on the CD/Radio display and the burned out lights (if they're linked to a feature or function) seems to also kill that feature or function. I cannot select disk 3 on the CD Player nor can I get to my FM Preset on Button 3. Seemingly because the display light above this button is out. Or maybe the lamp is out because of a contact problem at the board level. Who knows?
I'm logged on today looking for someone who does board level repairs and/or exchanges on these very costly electronic parts and control panels. The dealer prices for replacement/exchange start in the low four figures. While I love this car, I'm not going to pump another two grand into it just to get the Radio to function completely - or not if there's another choice anyway.
BTW: IF ANYONE has a company who will do board level repair/replacement on the Climate Control Heads / Radio/CD/Tape unit / Dash Displays / PLEASE LET ME KNOW. It's obviously cheaper to get these replaced at ONE time rather than incurring three or four different labor charges for tearing into the dash and putting it back together with the replacement parts.
Thanks
Marki
I have a 98' 740IL which has many electrical problems which have shown-up only to have them seemingly fix themselves. The problems include:
------------------------------------------------------------------
- The radio quits working.
- The OBC monitor goes blank / the dash display of information by pressing the button on the end of turn signal displays proper information.
It suddenly starts working after a few/many days.
------------------------------------------------------------------
- The Check Brake Light comes on.
It will suddenly goes off after a few/many days.
-------------------------------------------------------------------
- Check Engine light comes on.
It will suddenly goes off after a few/many days.
-------------------------------------------------------------------
- Turn indicators fail to display but the lamps flash as usual.
- Highbeams are not indicated on dash display, but headlights work as usual.
They suddenly work properly after a few/many days.
------------------------------------------------------------------
What could be the problem?
Larry
Flywheel
12-24-2004, 02:07 PM
Just to add a few ideas to good advice that John provided:
Some of the dashboard wierdness may be caused by failed capacitors on the dashboard circuit board. To get to it you have to remove the steering wheel which means you have to remove the airbag, so don't try it without very good instuctions.
On the earlier E32 models, like mine, the Light Control Module (LKM) has infamously bad solder joints at the relays which can cause some really strange things. I think this module is located under the hood or behind one of the footwell panels.
In addition to this one, another good site is www.roadfly.org, which has a different forum for each chassis. I've surfed the E38 forum and most of the owners there pay to have their cars fixed, while on the E32 most owners fix problems themselves since they/we tend to be less wealthy. Look at the E38 forum first but also remember the E32 forum. Also, the search engine for that site seems to be forum-specific. Good luck.
The LKM you mention certainly can play games with your external lighting. As you said, the soldered joints on the little relays do tend to dry out and crack, causing intermittent problems. The LKm itself is located in the engine compartment. On my Right hand drive (Irish) car, it's right up under the windscreen on the passenger side, inside a black box, about 8 inches by 6 inches. The cover on the box just snaps off and there are a few modules inside, but the LKM is clearly marked "LKM" for Light Kontrol Module. The Module just pulls straight up and out, though it might be a little tight, but it will shift. When you have it out, gently prise the outer casing apart at the end where the pins are and the internal printed circuit board will come out. You'll see the little relays at the corners of the board, and there usually just need to be resoldered where they fix to the board. Hope this helps.
Some of the dashboard wierdness may be caused by failed capacitors on the dashboard circuit board. To get to it you have to remove the steering wheel which means you have to remove the airbag, so don't try it without very good instuctions.
On the earlier E32 models, like mine, the Light Control Module (LKM) has infamously bad solder joints at the relays which can cause some really strange things. I think this module is located under the hood or behind one of the footwell panels.
In addition to this one, another good site is www.roadfly.org, which has a different forum for each chassis. I've surfed the E38 forum and most of the owners there pay to have their cars fixed, while on the E32 most owners fix problems themselves since they/we tend to be less wealthy. Look at the E38 forum first but also remember the E32 forum. Also, the search engine for that site seems to be forum-specific. Good luck.
The LKM you mention certainly can play games with your external lighting. As you said, the soldered joints on the little relays do tend to dry out and crack, causing intermittent problems. The LKm itself is located in the engine compartment. On my Right hand drive (Irish) car, it's right up under the windscreen on the passenger side, inside a black box, about 8 inches by 6 inches. The cover on the box just snaps off and there are a few modules inside, but the LKM is clearly marked "LKM" for Light Kontrol Module. The Module just pulls straight up and out, though it might be a little tight, but it will shift. When you have it out, gently prise the outer casing apart at the end where the pins are and the internal printed circuit board will come out. You'll see the little relays at the corners of the board, and there usually just need to be resoldered where they fix to the board. Hope this helps.
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