Will it boot with the trackpad disconnected?

You may have an easy fix here! So let’s not throw the baby out with the bathwater!

To be clear you need the trackpad connected as it has a thermal sensor SMC requires. If you disconnect it you’ll face a very slow system! As SMC will place the system is Safe Mode cranking up the fans and lowering the CPU’s clocking so it won’t over heat.

OK lets fix your system! You’ll need to fully remove the trackpad as its gotten gummed up! Follow this guide MacBook Pro 13" Retina Display Early 2013 Trackpad Replacement follow it to Step 9 removing the interposer board, then jump to Step 21 & 22 removing the SSD.

So far we’ve jumped over a lot of steps which are not really needed. I’ve found an easier way!

Now we do need to jump to Step 35 & 36 as we need to disconnect the trackpad cable so we can slide it out but if we do that without removing the battery we’ll have a hard time getting it back! So we need to attach a pull back to the cable!

Basically, taking a strip of electricians tape attached to the tab and the cable that we can reach and then taking a second strip to cover the adhesive surface about eight inches. The battery is not glued to the cable but we will need to carefully raise it a bit without damaging it at the logic board end. We do have a strip of adhesive holding the cable down just inside the SSD hollow (you can see it in Step 39 first image). Use a thin spatula to carefully lift the cable off. Now carefully pull the cable through a bit about an inch.

Now Jump to Step 40 & 41 removing the screws and plates Then in Step 42 we’ll push the cable slack through the slot so we can then get the trackpad dislodged. Once its loose you can then gain access to the back side to disconnect the ribbon cable from the trackpad. I do recommend to use a sharpie to mark the cable so you know which side the cable goes in. Carefully lift the clamp bar to release the pressure on the cable.

OK, we've got it out now what? Surprisingly I find using some cleaner along the upper case edge as well as the trackpad is all thats needed to clean things. You want a just damp micro-cloth (to much will damage the trackpad). I would just use fantastic spray a short spray onto the cloth is all I do.

Once clean reverse the order! After you put the trackpad screws back in give it a test. Do you hear it click when you press? You should see the trackpad depress ever so slightly.