My A/C is blowing hot air. I think it needs to be recharged. I know the A/C back then used R12 refrigerant. Can I change it over to R-134A? Also need to know where the low side port is located.

 

Start w/ what year/trim/country of use for your accord.

Generally, the low side fitting is the large diameter hose connection and returns from firewall to compressor.

Retrofitting is likely the best option to restore AC function. It's a good bit more than filling w/ R134a; new fittings, flushing, leak inspection, new lube installation, vacuuming, and charging.

good luck