I have had my fender jaguar (CIJ) for about a year now and it seems very weak with the sound... comparing to my stratocaster MIM, the top pickup of the jaguar is just as loud as the the strat... with both pickups on it seems quieter and with bridge pickup on... it seems to be quiet, but still making sound.

I'm no tech, but im semi-aware all the electrics are working fine. if i tap an allan key on each pickup (even when selected to the one pickup) they are all just as loud as each other...

the pickups are at equal levels to the strings.

I've been recommended pot cleaning... but don't know how to use it and i can't quit see how it affects this.
check fender's site for recommended pickup heights. you may find that the pups aren't as strong as a strats as well.
Pickup heights aren't always the answer (sometimes though!) with japanese jaguars. A lot of them have awfully weak pickups, and that's just a fact. I recently bought an MIJ Jaguar and was worried about weak pickups, but luckily they were fantastic. It's all luck of the draw.

Fender is about to start selling their American Vintage '65 pickups from their US Jaguars, and they should be incredibly affordable. Those will make a giant difference in your guitar if you can get your hands on some. There are also seymour duncan pickups available that make a big difference.

Do some google/other forum searches for weak jaguar pickup solutions, you'll find a lot of replacement recommendations.

Of course, that said, definitely try raising/lowering them a bit first. It could be that simple!
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