Amp keeps blowing fuse

The fuse is blowing due to an overload. It's often and very likely caused by a transistor or ic that has gone short. The main culprits are the power transistors of the amp or whatever is on the big heat sink. Transistors will show the fault when you connect an ohmmeter to the terminals. It will be just like you have touched the test prods together! I don't think in your case it will be in the power supply. It's often caused by speaker cables that touch together.

1. Stop going to this shop.
A fuse that keeps blowing is a sign of a problem. You never replace a fuse with one of a higher amperage because the idea is the fuse is suppose to blow before the the wires melt and catch on fire. The reason it stopped working and the fuse didn't blow is probably be cause the wire did melt someplace and you are lucky the car didn't burn. If it did burn and the insurance company found the 40 amp fuse, they would probably have refused to pay.
The idea that a repair shop would do this tells me that they don't know what they are doing. Read this
FUSES

I will assume the ac is still getting cold, just not blowing.
You wouldn't really know unless you pulled the panel and checked the lines.
Causes include the blower motor, resistor, fuse, or switch.

Your wiper motor is about to go out, if it hasen already, wiper motor pulling to many amps will cause the fuse to blow.

you may of caused a short in the connections or it got moisture why in storge if so the hole subwoofer is screwed

check the all power lines and regulator .is any of them overheating?
then check the power amp ic or transistors.

nuwan.

this is in response to the post below:

I just bot a basslink t and i wired it up and nothing it just keeps blowing the fues in the unit i got mine on ebay so i dont know if i can use the warranty dose anybody have an ida for me- britter623

I got a used basslink about a month ago and had the exact same prob kept blowing fuses...found out that the voice coil had blown on the infinity...so I had a brand new dvc polk 10 sittin in the closet, I swapped them out, put the polk in the place of the infinity sub, however, the magnet is much larger, hence, dual voice coil, it would rattle sooo much from the passive radiator against the magnet, also could not turn the gain up at all due to the rattle. I got the bright idea to build a "custom fiberglas enclosure for the polk and incorporate the infinity's parts(amp/control) I finished the box finally last night and hooked it up this morning, no power, no lights, no nothing! s@#%, F&@%! ANyone had a prob w/the amp not having the lights turn on, no power??? Hope that helps about your fuse blowing issue.

check all your power fuses and insure you havec power where it is supose to be. maybe you have blown a fuse.

check the power cables on the amp and the inputs.isome time when ground cable disconnect the lioghts will light up any way. depending on the way ur vehicle is ground ed .toyota chssis r usually posite un like the norm which is neg.rating please

You may have blown the fuse in the AMP. Check it and let me know.