1991 325i SRS light doesn't come on

[salvadorwill]

When I turn my car on the seat belt light (in the check panel) turns on, but the SRS light never does. I have made sure the bulb works, and made sure its not the check panel itself, but the light doesn't turn on. Make me think my SRS system doesn't work at all. I've checked the connectors under the hood, tried jumping pins 1 and 6, and still nothing. I have done a ton of searching, and haven't found an answer to what the issue is. Anyone know what could be going on???

[roguetoaster]

Is the orange box under dash still present/plugged in? The connector isn't something that can just be pulled out, so if disabled the steering wheel was likely removed and swapped back.

[salvadorwill]

I haven't checked that orange box, will do it today. I have pulled the steering wheel before, but I followed all the proper procedures (disc batter, wait, etc...).

[salvadorwill]

When you say under the dash, where is it? I looked in the area above the glovebox where the main control unit is and there was no separate orange box.

[roguetoaster]

When you say under the dash, where is it? I looked in the area above the glovebox where the main control unit is and there was no separate orange box.

Below and forward of the headlight control knob, at least on a LHD car.

[salvadorwill]

Thanks, found it. Its there and plugged in.

[roguetoaster]

Thanks, found it. Its there and plugged in.

Well, it's probably inoperative. Unless you need the SRS system to pass an inspection (you shouldn't) you should just ignore the fault, swap the steering wheel and make sure your seat belt is in good condition (always a good idea).

[Vincenze]

https://www.armchair.mb.ca/~dave/BMW/e30/e30_91.pdf

Disconnect the 6-pin connector C240 from the SRS block. It's probably better to disconnect the battery before doing that, and connect it back after you disconnect the connector.
Connect the pin #1 (Brown/Black) to the Ground and turn on the ignition key to the ACCY position. The LED should light up.
Check the pin #4 (Violet/Yellow). It should have 12V.

[salvadorwill]

I have to make everything on this car work, I'm obsessive. This is one of the only features I haven't restored, so I am gonna try and figure it out.

[salvadorwill]

https://www.armchair.mb.ca/~dave/BMW/e30/e30_91.pdf

Disconnect the 6-pin connector C240 from the SRS block. It's probably better to disconnect the battery before doing that, and connect it back after you disconnect the connector.
Connect the pin #1 (Brown/Black) to the Ground and turn on the ignition key to the ACCY position. The LED should light up.
Check the pin #4 (Violet/Yellow). It should have 12V.

Thanks, I will give it a shot. When you say "the SRS block" I assume that is the orange box behind the headlight switch, right? And by "LED should light up" you mean in the check panel? Just making sure I'm clear.

[Vincenze]

Thanks, I will give it a shot. When you say "the SRS block" I assume that is the orange box behind the headlight switch, right? And by "LED should light up" you mean in the check panel? Just making sure I'm clear.

Yes, the SRS computer. There are some on eBay, they are not very expensive.
If I remember correctly now, it's not an LED, but a light bulb, it can be changed from behind the check panel.

I just followed the wiring diagram from the link above.
If there is an error in the SRS system, that bulb must flash, and you can count the flashes to find the error. But if it doesn't flash, then the SRS computer can be dead.

[salvadorwill]

Did some tests, here is what I found:
The connector coming from the unit has the same colors/locations as what you show (#1 Blue/Bk, #2 Wt/Vi, #3 empty, #4 Gr/Vi, #5 Bk/Yl, #6W/Yl). On the side that plugs into that connector it goes: #1 Br/Blue, #2 Empty, #3 Red, #4 Violet, #5 Bk/Gr, #6 Wt/Bk. I tested pin #4 violet, and no power, however pin #3 red does have 12v. I also tested connecting pin #1 Br/Bk to ground, no light. Tried it with and without power. Only idea at this point is that the unit is dead, but also wondering why my wires differ from the wiring diagram. Why does my violet not have power, and this random red one does?

[Vincenze]

If there is no Power, it doesn't mean that the SRS module is dead.

You should follow the Violet wire to the connector C200, pin #4.
It should have power when the ignition key is in the position ASSY.

Check the view of the connector C200 on the page 142: https://www.armchair.mb.ca/~dave/BMW/e30/e30_89.pdf
It says that the 10-pin connector should be on the steering column. It should be connected to the ignition lock.

You'll probably have to take out the steering wheel to disconnect the plastic covers around the steering column.

[salvadorwill]

I do have power, just not on the pin#4 violet, instead it is on pin#3 which is a red wire.

[Vincenze]

I do have power, just not on the pin#4 violet, instead it is on pin#3 which is a red wire.

You say the the pin #3 is not connected to the SRS module.
It's not in the diagram. It can be obsolete.

According to the diagram, the power must come from the violet wire.
Another violet wire coming from the same connector C200 should be connected to the pin #4 of the connector in the check panel.