door locks/interior lights/sunroof/windows inop

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I'm having a bit of problem when the ambient temperature reaches the mid 30's and lower. My door locks/interior lights/sunroof/windows become inoperative.

I have cleaned the battery terminals and removed and cleaned the fuse link strip under the plastic housing mounted near the battery.

Any Ideas would be appreciated.

The car is a 1991 535i.

Thanks,
Chris

[Javier]

then the issue comes from GM/RM modules. Check good connection in their sockets for: Fuses F17, F24, F30, F47, Relay K15, and modules GM and RM. This picture will help you identify some of the items below the rear seat.



I would plug/unplug the relay K15 (Power Protection), as if he is not activating properly (you should feel the click when plugging in if key is in running position), power is not reaching windows/locks.

The issue may be as simple as a damaged/overheated fuse socket or fuse that disconnects under freezing cold. You can help yourself identifying the culprit with an hair dryer, point to specific items, and see if warming them solves the situation.

Note: Battery should be disconnected to plug back the GM.

Javier

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Yep also the wipers only work on high. Thanks for the tips. Perhaps in the morning (in the 20's) I'll be able to check it out .

Thanks agian,
Chris

[Javier]

be as simple as a broken fuse filament, that shrinks under cold and disconnect power to control circuits in GM.

Javier

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can a single fuse cause all these malfunctions?

[Javier]

for operating windows, locks, Wipers special functions (High speed is keept appart for safety), and Automatic interior lights.

This is achieved trough the RM (Relay module). If for example you loose F30 that powers the coils to the relays in RM, and some functions in GM, you will loose all GM operations.

Javier

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Javier,

I finally got around to testing the circuits in my car causing me cold weather problems. It is in the upper 20's here in Huntsville, AL this morning, and all of my window/wiper/lock/sunroof/etc. are non-functioning.

thanks for the procedure you posted on 11/6/05 fo drmmaster. I went throught the ground and voltage checks and everything checked out OK. I have good grounds and 12.9vdc power where it is supposed to be.

I opened the GM to look inside. I saw a bunch of little crap! That's technical talk for a mechanical engineer looking at a circuit board. I put it all back together (GM & LM) hooked up neg battery, and everything came back to life.

Where do I go now to determine if infact the GM is "bad" during cold weather?.

Thanks a bunch.

Chris

[gruffalo]

hi,

I have the exact same problems. I have voltage everywhere, but the GM shuts the PPRelay off. So I guess it's either GM failure or a reason for the decision to shut the relay off.

What causes the GM (assuming it is OK) to kill the PPR?

MM

1990 525iA m50

[duckloads]

I don't know if the gm shuts the ppr off or if its the other way around. Here are some tests to determine if your ppr is bad. Relays do sometimes go bad.

If I warm my GM up with a hairdryer then everything works again.

[Javier]

Inside the GM, there is a series resistor, which measures the total current flowing to most devices controlled by GM. Whenever this resistor exceeds a pre-set voltage (which means current trough it exceeded a preset value), the GM cut power to the PP Relay coil. If the resistor is damaged, or excessive cold shrink its leads, causing them to increase connecting resistance in the soldered joints to the PC board, then total resistance is greater and under low current can trigger the PP relay.

I would check carefully the GM PC board looking for trouble in that resistor. Check this link for further info. This of course, if PP is dropping or not engaging at all, being it in good shape. Note that if resistor is opened, no mater the PP relay status there is no power flowing into the GM controlled devices.

http://www.bimmer.info/forum/showthread.php?t=9950

Javier