What is this part and what does it do?

[JPHedberg]

Tried searching for an answer with no luck, so hopefully somebody can give me a quick answer to my question...

Recently picked up my 2nd e30, this one is a 84 318i. I am doing some lightening/simplifying on the car and I came across this small metal box.





I know I have seen something similar in the past, but for the life of me I cannot remember what it is or what it does...

Looking forward to an answer, and very happy to be an e30 owner again!

Thanks,

Josh

[E30_Pare]

Never seen anything like that. If I had to guess. Mount for air box? Some how?

[JPHedberg]

Never seen anything like that. If I had to guess. Mount for air box? Some how?

It didnt mount to the air box so I am sure it has nothing to do with that..but I will go to the garage and snap a few more pics of exactly where it mounts and such and post em right up. Thank you for the suggestion!

[E30_Pare]

I'm thinking some one made it to mount like a filter.

[Jaxx_]

I'm thinking some one made it to mount like a filter.

it looks to be body colored, so it probably left the factory like that unless someone did a nice respray.

[JPHedberg]

OK so I am certain this is aftermarket and was added to the car no too long after it was purchased. I took pics of everything I saw when I dug deeper, I will post them up shortly!

Thanks

Josh

[JPHedberg]

It was suggested on another forum that it could be aftermarket cruise control or alarm stuff. I think it was likely part of an alarm at some point.

Heres some more pics of this thing, definitely old.

Everything Removed:


This wire ran was running up the cruise control harness and capped, factory cruise control unit? :


Following red wire and black presumably ground wire...they were zip tied to a factory harness, at one point the wires were connected to a different set of two wires with butt connectors:


It disappeared under the brake booster, gave it a little tug and out came whats left of the wiring:





The internals of box:

[E30_Pare]

Could have never guessed that.

[JPHedberg]

I think the mystery is solved, on another forum somebody suggested its a ghetto motion sensor for an alarm system. And looking it over in more detail, I'd have to agree!

[autbot318i]

i had the same in my 318i from PO. it was def an alarm piece

[solo318]

definitely a motion sensor from the mid 80s.