I can’t find the a/c clutch relay. I need to bypass it so I can add refrigerant

 

You could jump the low pressure cutout or directly feed +12V to the clutch, and erase the need to locate that relay.

 

When mine was low enough that the low pressure switch wouldn't close to allow the compressor to run, I measured low side psi to confirm psi was just a little low, so chose to Purge my gauge set of air with refrigerant, connect it & Slowly add refrigerant Gas to the Low pressure side until the pressure rose enough so the low pressure switch closed & the compressor would run (for me it was about 1/8 - 1/4 can). ( Don't get in a hurry & tip the can up to add Liquid to make things go faster. Keep the can Upright so to only add Gas slowly as the system will take it, to the low side when charging.) That way when the compressor started I knew it had enough refrigerant in it to circulate the oil to lube the compressor without forcing the system to run & not have enough refrigerant in it to circulate lube for the compressor. The compressor will appreciate that.

Lots of unknowns here, I'm assuming you've fixed the leak, flushed the system, added the correct oil by volume, or weight, replaced the dryer, evacuated the system to remove any moisture & air & are now ready to recharge by Weight, not just adding some refrigerant because enough has leaked out to cause the low pressure switch to open & protect the compressor from running without lube.

If you have a leak that you haven't found & its really small / slow & not showing signs like bubbles on a wet down test with soapy water of all the connections & hoses, or showing any oily signs of lube escaping the leak, try adding some refrigerant with a UV dye in it & see if that'll help spot the leak with a UV light at night so you can see the dye glow better, all so you can fix it & evacuate the system & recharge it by weight, which is the way we're supposed to do it.

If it's lost a good bit of oil, it would be a good idea to flush clean the system & also add the specified volume of new oil, then evacuate & recharge by weight.

If your not going to do all that, just top off with a little refrigerant like I had to a couple of years ago, Don't add too much, say not more than one can. I used my gauge set to monitor the Low & High pressure sides while Slowly getting the low pressure side within the specified chart psi range for the ambient outside air temp while I was recharging, with the vehicle cabin circulating fan on High speed, so as to try & Not over charge & harm the compressor. (for me it took 2/3 - 3/4 can to get low side psi in range with good cooling at the registers)) It's not the right way to do it but if like me you have to do it this way right now, take your time & Don't add too much refrigerant. More charge won't make it cool better, just overwork the compressor if the high side psi gets too high.

More thoughts for consideration, let us know how it goes.