A/C low side refridgerant inlet port
 

Where is the low side refridgerant inlet port on 2002 B3000

I don't have hands-on experience with these 1994-on Mazda/Ford Ranger trucks.

However, the low pressure service valve MUST be between the evaporator (inside the dash) and the compressor. I suspect that the service valve could be on the accumulator itself, but could be on a low pressure line itself, possibly even at the compressor itself.

1. Have you taken a good look?
2. If the system is low on refrigerant, then there IS A LEAK, which must be fixed before adding refrigerant.
3. NEVER, EVER, ADD SEALER OR REFRIGERANT CONTAINING A SEALER !!!