[blbrchnk]

I posted this in the electronics section, but it may be better off here. I purchased a 335i with upgraded RB turbos, inlets and the whole shebang from a user on this forum. Car has been running great for months and still does, but lately I have noticed that this relay has been clicking super fast constantly under the hood. I think the previous owner did the coolant expansion tank relocation so I don't believe this is the original location of said relay. The relay is a HKE CMA31-CM 30Amp 14VDC.

Anyone know what it controls? Advanced Auto said it was for the O2 sensor. When I unplug it, I lose my HIDs, so I am all over the place with it. I bought a replacement, but it clicks as well so I am thinking the relay itself is fine. It does seem to be making more exhaust which would make sense with the "O2" theory, but then why would I lose my HIDs when it is pulled

Here is an image of it. If anyone has any ideas, I'd appreciate it.

https://goo.gl/photos/gu5ANpNP9GqhFEzD8

[MysticRob]

I think you answered your own question. Unplugging an O2 sensor won't cause your HIDs to go off. Googled that part # and I saw relay for headlights.

It's possible someone did some mods on your car that is causing the cycling on that relay. I'd look there first. Also, where's the relay originally mounted, and where is it now?
I ask because it may be a heat-related issue causing that relay to cycle so much too.

[blbrchnk]

Originally Posted by MysticRob

I think you answered your own question. Unplugging an O2 sensor won't cause your HIDs to go off. Googled that part # and I saw relay for headlights.

It's possible someone did some mods on your car that is causing the cycling on that relay. I'd look there first. Also, where's the relay originally mounted, and where is it now?
I ask because it may be a heat-related issue causing that relay to cycle so much too.

I have no idea where it was mounted originally. Now it is up front close to the passenger side headlight. I will try to trace out the wiring later this evening. The odd thing I noticed while driving it today was that it seemed to cycle more when I was on the gas and not hardly at all while breaking. Maybe that was an uphill/downhill or momentum thing causing a shorted wire to move, I don't know, just found it to be odd.

I guess the O2 thing doesn't make much sense because I imagine the car would have told me about that.

Thanks