Hello. I will try to make a smart key of my volvo car key. I have a problem and that is where am going to solder on positive and negative on the circuit board? I will provide some pictures on how it looks. Thanks.
After looking at it closer:
In picture of PCB:
You have the red + and black - reversed. Bit of a weird design to be honest. I wonder if one battery is for PROX functions and the other for keyless entry functions. The picture of the shell with the red + you have is wrong as well, that is B- according to diagram.
Just a heads up. Volvo keys are some of the most expensive keys to replace. I'd refrain from doing anything to it unless you have another key or if you fail at your task, are ok with getting a new one. Not sure what model year you got but it wasn't uncommon for me to charge $500-650 for replacement volvo keys & programming.
I added a picture to my original post, Sorry for all the edits, I didn't look at it originally and assumed it was like most other fobs I deal with. I later looked closer and realized this one is an oddball.