Dell Inspiron 1525 OEM Mouse Buttons Board
2014-11-01 Final update: Both parts fit well.
By accident another part worked well. I received that part which had 3 wires from eBay and gave it a try – and it worked!!!
To conclude, there is no difference between number of wires and parts. Initial assumption was wrong because replacement part was damaged.
Today I decided to fix my Dell Inspiron 1525 touch pad mouse buttons board.
Accidentally I discovered that exists two versions of these button boards with same part number.
The visible difference is number of wires in the cable. Mine had 4 wires, whereas other part had 3 wires in the transparent cable.
So, before buying check this important difference, otherwise mouse buttons just won’t work.
If you take apart both parts, you will see other obvious difference in how mouse buttons are attached two the board. Both bords have very different mouse button construction. But this is not visible when buying replacement part.
I strongly recommend do not take apart mouse buttons ever, because their fixings break very easy.
To summarize, check the number of wires in the transparent cable before buying replacement part, as both parts have same OEM numbers.