1991 325i SRS Airbag module questions

[salvadorwill]

Anyone a pro when it comes to the Airbag SRS module for the E30? My question is that my module (65771377458) is dead, and I am looking to replace it. I know that this same part number was used across various models, so does that mean it needs to be coded in for the specific model its installed in? Did they do coding that far back? The model number is Siemens 5WK4 035, and the bar codes are 3113774585 and 3502801403. I am thinking that the bar codes on the side are important, perhaps they are what ECU and model the unit is compatible with?

Can you take this same module from a 318i or a 635csi (they also used this pn) and just swap it into a 325i and it will work fine?

[bmwman91]

If it is the same PN then it should be fine. There was no CANBUS or anything on these cars, and the SRS module does not communicate with the DME or anything else. Obviously you'll want to make sure that the replacement works too, but any module with the same BMW PN should be fine.

Also, how do you know that it is dead? I am not familiar with any test procedures for it, so other than it not deploying the airbag in a collision, I am not sure how one would ascertain the functional status of the thing.

[Vincenze]

Also, how do you know that it is dead? I am not familiar with any test procedures for it, so other than it not deploying the airbag in a collision, I am not sure how one would ascertain the functional status of the thing.

It should flash the SRS light when there is an error. Then the flashes can be counted to find the error code.

If it doesn't flash at all, then it's probably dead, unless there is a wire connection problem.