I am having trouble starting my 2003 S60 2.4L non-turbo

[jonesg]

if he used chinese part thats the first suspect.

is it this ?

[dikidera]

Is your model a bifuel one? If not, then it's likely a short somewhere. The electrical installation on these cars is now over 20 years old and the insulation has cracked is my opinion which is why the fuse blows. I would definitely disconnect the vacuum pump and see how the car behaves that way.

[kcodyjr]

Sounds to me like he pinched part of the wiring harness doing the work, and now it's intermittently shorting to ground.

[abscate]

Sounds to me like he pinched part of the wiring harness doing the work, and now it's intermittently shorting to ground.

That’s on point and highly likely to be the problem.

Fault trace the fused circuit that is failing looking for bad wiring.