Hi all.

Having to replace my body control unit or jbbf unit but before I do, would like to know what the H1 stands for on the top of it.

I have been searching for one on eBay and I have found many, in fact loads!!!

My current one has H1 but some I have seen on eBay have H4 or even an L letter.

I have found that some also have the black and blue connectors the other way (mine has black on the left and blue on the right) and have figured that the LCI models are the ones with blue on the left.

So my question is, if I "upgrade" my current one to one with H4 and an updated software version, will this still work on my car.

My car is a 2005 E90 with halogen lights and fog lights front and back.

I know from previous jobs the FRM has letters to indicate what type of lights it will control and assume this is going to be the same for the JBBF.

If anyone could answer my question, that would be great.