Cadillac Repair: AC clutch fuse blows, fuse blows, compressor clutch

Question
QUESTION: I don't know if my 2002 Buick Century is something you can give advice for but there are no experts on the Buick forum. My underhood 10 amp mini compressor clutch fuse blows after spining the clutch for several minutes. The compressor clutch mini relay is next to the fuse and I temporarily swapped it with the horn mini relay but same result. I recharged the system the night before after changing the mini fuse and the clutch stayed locked up until I stopped engine. Upon restarting car no AC because the mini fuse had blown. I checked the electrical connection at compressor and everything looks brand new inside. It is a 3.1 litre engine. Any obvious things come to mind that I am missing.

ANSWER: I would have to say that you most likely OVERCHARGED the system with freon.

WHY did you have to recharge the system and how much freon did you install ?.



---------- FOLLOW-UP ----------

QUESTION: Hi again,
Tried to use AC for the first time this year and got nothing but hot air. I assumed the system had lost freon so I bought a recharge can at the store. When I connected the gauge that came with the can to the low side connection it read way up in the overfull zone, around 70 psi on the can gauge. That is when I discovered the clutch was not locking up. I checked fuses on side of glovebox and under the hood and found the 10 amp mini fuse under the hood had blown sometime in the past. After changing that fuse the clutch locked up and I got a reading on the gauge of 25 psi, according to the can that was low for the ambient temp outside of 85 degrees. The can said 45-55 psi for that air temp. I let the system run for awhile and the temp at the ducts did go down but only about 15 degrees or so (my estimate), so, I already had the can and decided to add some to bring up to 45-55 psi. It took the whole 18 oz. can to get to 45 psi. with duct air nice and cold now. I turned of car and restarted and low and behold- no AC. Poped the same fuse again. I had a chance to buy more fuses and it takes less and less time to pop one. I can pop one in about 4 seconds now. The first time around before and during recharge it lasted 15 or 20 minutes. Does that sound like an overcharge, and if so how do I get it back where it should be?

Answer
If you had to add that much freon to the system, Then you obviously have a leak in the system. What you need to do is check for a freon leak using an electronic leak detector, Fix the leak, Evacuate all the atmospheric air from the system by using a vacuum pump, Recharge the system with the required amount of freon.

You ALWAYS read the LOW side pressure with the A/C compressor running. If you check your high side pressure your most likely way over the maximum pressure limit which causes the compressor to strain which causes the fuse to blow.