[mutyo051026]

I have 03 525i sedan and recently the right tail light failed due to the melting ground pin of the wire connector. Since both connectors of the wire harness and tail light assembly melted, I ended up buying new tail light assembly and wire harness from Amazon.com, which costed about $160 USD. It seems like many people who own E39 had the same issue, but I am really curious what are the possible causes of this issue. I haven't received new parts yet, so I want to know what I should do to prevent the ground pin from burning out before installing the new units.

 

[acoste]

Heat is generated by a too small contact area. In your case it might mean that the connections are lose.

pull out all the female and one male connector out of the case: push that little tab on the connector with a pin that is near where the numbers are pointing on the figure below and pull it out backwards by grabbing the wire. (take a pic to remember the wire order)

And then mate the female and male parts, see if they are lose. If they are, you can adjust the female part by pressing it together a bit.

 

[jfmjr442]

check the wiring wear it enters the trunk in the right corner - see if the wires inside black rubber are cracked/shorting out

Mine were cracking and i have heard of others - similar to E36 trunk wiring issue

HTH

John

 

[edjack]

Examine the old connector pair for corrosion. This can cause resistance and heat.

If you find some, it's likely because the battery is not properly vented: The battery should have the small vent tube attached to the front face.

Not an uncommon failure.

Might want to remove the spare and look for corrosion there.