General module problem

[liljos]

in addition to my other problems, i believe I have a general module problem. none of my interior lights work besides the visor lights as those are on a completely different circuit and will only operate if 1. the exterior lights are on (city or fully) and 2. the slider for the mirror is open. my question is (since I don't wanna buy a new one) can i possibly repair my GM? such as resolder old/bad connections?
note: money isn't the issue so buying one isn't out of the question. and I have the black GM. is that found on early
cars or later models? mines a 1990 525i m20

[whiskychaser]

I think you might look at the light control module (LKM) rather than the general module. In which case this could be handy:
http://www.bimmernut.com/forum/5-series-bmw/43676-lkm-resoldering.html
Erm ... you have got the light switch in the right postion havent you? ;)

[shogun]

interior lights = GM.
headlights are LKM.
You can try any GM. In case you have a new GM, here the complete official info:

This Service Information Bulletin supersedes S.I. 61 01 92 (3460) dated January 1992. It incorporates additional information on the new General Module software for E32/E34 vehicles. Please remove and discard S.I. 61 01 92 (3460) dated January 1992 from your S.I. Binder.

SUBJECT: New General Modules (GM)

MODELS: 7 Series (E32), 5 Series (E34)
- Vehicles produced 9/91 and later
Situation: New general modules have been used in production since September 1991 in all E32 and E34 models. The software has been completely revised (details of these revisions are found in the attachment to this Service Information Bulletin). Part numbers have been changed to reflect these revisions, as listed below, as of September 1991. Model Part Number
E32 61 35 8 356 095,
E34-up to 61 35 8 356 095 9/91 production
E34-9/91 and later production 61 35 8 355 812
Note:
E34 vehicles produced 9/91 and later have different central locking system components from earlier E34 vehicles; therefore, P/N 61 35 8 355 812 is used only in E34 vehicles produced 9/91 and later, P/N 61 35 8 356 095 can be used in E34 vehicles produced prior to 9/91, and in all E32 vehicles. When the general module is connected to the vehicles electrical system, it will recognize (and store in memory) the vehicle configuration, such as:
- with/without power windows
- With/without power sunroof
- with/without wiper contact pressure control
- with/without headlight washers
Important Information
All general modules must be plugged in only after disconnecting the vehicle's battery. If the vehicle's battery is connected when the GM is installed, undefined signal contacts can cause an incorrect vehicle configuration to be stored, resulting in the impairment of one or more of the above-mentioned systems. If one or more of the GM functions are impaired in this matter, the GM can be "cleared" by disconnecting the vehicle's battery for at least ten seconds.
Warranty Status: Information only.
Attachment to S.I. 61 01 92 (3460)

GM Function Changes E32/E34 (Beginning with 9/91 Production)
- Repeat and Time interlock for headlight washers:
· Time interlock: 3 minutes
· Headlight washing at fifth windshield washing after time interlock.
- Intensive washing pump operating time reduced from 3 to 2 seconds
- Minimum interval for intermittent wiping is programmable down to 2 seconds (previously 3 seconds)
- Increased wiper contact pressure during windshield washing cycle is now also provided during dry wiping portion of the cycle (previously only during washer pump operation).
- Previously, the GM would react to opposing signals (eg., an unlock signal while trying to lock, as with a defective microswitch) by carrying out the first command, then the opposing command (e.g., locking, followed immediately by unlocking).
Repeating the first command then results in carrying out that command (e.g., try to lock again, and locking is now carried out).
This function ("Asynchronous Position") is omitted in the new GM for all E32 models and E34 models prior to 9/91 (P/N 61 35 8 356 095), and remains in the new GM for E34 models after 9/91 (P/N 61 35 8 355 812) only for central locking commands "lock" and "double-lock".
- After unlocking is performed due to crash sensor activation, the locking command is now reactivated by double-locking with the key from either the driver's or passenger's door.
- The "one-touch" operation of windows has been expanded to include all four windows in the opening direction. The driver's window still has "one-touch" operation in both opening and closing directions. Interruption of the "one-touch" feature of the driver's window in the closing direction is still accomplished by depressing any window switch (in any direction), or by depressing the sunroof switch in the "tilt" direction (provided the sunroof is not already in the "tilt" position). Interruption of the "one-touch" feature of the sunroof in the closing direction is still accomplished by depressing the sunroof switch (in any direction).
- The switch-off delay of the interior lights which occurs after entering the vehicle and closing the driver's door has been reduced from 20 seconds to 15 seconds.

[liljos]

you really know exactly where to get the best info on thesetopics. I'm thinking of upgrading my 1990 GM to a 1995 GM. any ideas or comments on that?and shogun that is good information that I'm gonna use but my real question is am I able to repair it? I read on these forums that a member heated up his GM with a blow dryer and reported that it started to work after he did that. I haven't personally tried this but I plan to

[shogun]

yes, we also have repaired GM modules, just open it up and have a look for cold solderings and resolder/reflow them, basically what you do with the LKM, CCM and all the other modules in your car.
That is a basic check for cold solderings.
Electronic Repair Tips & Circuits: Electronic Soldering (http://electronicszone-shiharan.blogspot.com/2011/02/electronic-soldering.html)
Some are very easy to spot as they are dull grey and not shiny like the rest. Others are just a thin faint dull ring round the joint and need close inspection with a magnifying glass to see.

[liljos]

I'm gonna do that exactly when I get home. I'll possibly post pictures of what I see if that is useful.

[liljos]

ive decided to take the RM and GM out to inspect them both. i used a cheap magnifying glass to take a better look at the soldering. since i'm not a trained eye, i've only spotted a few that look cracked. but after comparing the soldering from the GM to the RM, the RM looks a lot newer. the GM looks dull and yellow. no build up around anything but the yellow discoloration might possibly be from a something that was applied at the factory. it appears to be a very thin layer. i'm gonna try to use some heat and see where it gets me.

[shogun]

the yellow "paint" is a protection for a board to withstand against damage due to contamination, salt spray, moisture, fungus, dust and corrosion caused by harsh or extreme environments.
Commonly used conformal coatings are silicone, epoxy, acrylic, urethane and Paraxylene. The chemical and physical properties of the materials differs and therefore offer different degree of protection.

[liljos]

hairdryer, tried and failed. /: and i had a feeling it was something like that