Can I fix the keyboard without replacing the Logic Board?

Hey all! I have been working on this Mac for this one customer for a few months now. Every time I get something fixed, something else breaks. First, the Mac gave me a prohibitory sign every time a booted. Then the trackpad stopped working, and now the keyboard is messing up. Turns out with the first issue, the Mac's ROM is slightly messed up, but I was able to loop around it and got the Mac to work. With the trackpad, I had to solder on a new button in order to click. With the keyboard, the customer told me that the space bar stopped working. When I got the Mac again, I found out the space bar, fn, and esc keys have all stopped working. After examining it a bit further, I found out the connector on the logic board seems to be the problem. The keyboard itself is okay, and technically so is the logic board. I was wondering if there is any way to clean the conector or maybe open it up to clean it. The customer doesn't really want to spend a lot of money on a new logic board because this one still works. Any ideas?