SRS Sensor

[18wheelerbob]

Hello, I'm new to the forum, I think it's great when a bunch of us Volvo owners can get together and share experiences and repairs. I just recently purchased a 2003 V40 with 57k miles on it. It was involved in right front corner accident and repaired and was given a PA Reconstructed Title. I live in N.Y. and have to do another inspection to our standards.
The srs light is on. The prevoius owner stated that a new dash was installed but never connected to the srs control module due to the fear it may blow and activate the air bag. He didn't have the OBD-II code reader to verify or I think it's a lie all together? But from asking around I decided to invest in a code reader and see for myself.( haven't recieved it yet) I was also told to just take it to the Volvo dealer and let them figure it out and repair it keeping the responsibility on the dealership. I really thought that was excellent advise, but I can't spare $1500.00 right now incase they make a mistake and want a way out by blaming the car (another faulty sensor). Someone also stated to change the passenger sealt belt and the right post sensor, then check to see if the pass. airbag is really not connected, if so, connect it, then run the OBD-II scanner and check to see if it clears? Advise is needed, especially in what order I start replacing the parts? Door post sensor, pass. selt belts or the srs control unit itself?