I've successfully performed this service before on my own vehicle, but I'm out of ideas on what's wrong here.
Engine running and fan set to low with A/C light on.
Opened only Low Side valve to allow R134a into system but the compressor didn't engage. Jumped compressor clutch at under-hood relay box, and clutch engaged but system doesn't seem to fill.
Low side pressure climbs but high side pressure stays below zero.
[Context]
22 year old vehicle; system was already empty of R134a.
Replaced valve cores on both Low and High side ports.
System holds vacuum.
Engine running and fan set to low with A/C light on.
Opened only Low Side valve to allow R134a into system but the compressor didn't engage. Jumped compressor clutch at under-hood relay box, and clutch engaged but system doesn't seem to fill.
Low side pressure climbs but high side pressure stays below zero.
[Context]
22 year old vehicle; system was already empty of R134a.
Replaced valve cores on both Low and High side ports.
System holds vacuum.