Repeated voltage regulator failure 2003 s40

[HotCocoa]

Yeah y'all I've been struggling with the alternator on my 2003 1.9t s40, The issue started last year while on a trip my alternator began to work only intermittently. This was the unit that was in the car when I got it in 2022, so when I got home I replaced it with a new unit from oreillys and that seamed to work for a few weeks then it died, so this time I replaced the battery and alternator that ran for about 2 months, did a 3rd warranty swap and it ran for a month then started not working again. This isn't a permanent failure it will start to work again after sitting for random amount of time. The last time it came back to life on its own. So fast forward to last week I just finished all new battery to starter/alternator wiring, my dad redid the grounds to the engine and body, and I added a new ground straight to the alternator housing. AND IT'S DEAD AGAIN..... I have checked the cem and fuze boxes for corrosion and bad solder joins didn't find anything. So are the voltage regulators from oreillys just trash and in that case do I need to bite the bullet and get a Bosch regulator? or is it something else. Thanks Paul.

[matthew1]

Welcome to MVS. I think a prudent next move would be a blue box voltage regulator yes. Part Number: 9472906

https://www.volvopartswebstore.com/prod ... 72906.html
https://parts.bobpenkhusvolvocars.com/p ... 72906.html

[Vova585]

We just discussed this on the other thread. Best way- take used oem alternator and take it to the professional rebuilders. Next best option-obtain used oem unit from erievovo or your favorite salvage yard and replace voltage regulator with bosch unit from fcp. Do not buy advance, autozone...even fcp only has reman units.