A code 37 is for the passenger side, side airbag. Just as a few here have suggested, the connector under the seat could be the cause. CAUTION!! ALWAYS, ALWAYS, ALWAYS DISCONNECT THE BATTERY AND WAIT AT LEAST 1 MINUTE BEFORE SERVICING THE AIRBAG SYSTEM. I should have stated that in my first post. The control module for the airbag system is looking for approximately 2 ohms through each of the side impact airbag modules. If the resistance is out of this range, the light on the dash starts to flash the code out. I have had this happen on my P5 for both front seats. Each time it has been caused by the connectors under the seats going high resistance. After carefully disconnecting the airbag module from the vehicle side harness, inspect the pins and sockets in the connectors and inspect for the general condition and cleanliness af the connectors and contacts. Spray cans of electrical contact cleaner are available at Radio Shack or your local brand auto parts store. A good shot or two into both male and female sides of your connectors should help clean them up pretty good.
You can do a simple check to see if your module is bad. You need a 2 ohm resistor (again, Radio Shack) After disconnecting the connector, you put the 2 ohm resistor across the 2 contacts on the vehicle side connector. This will be the connector coming from under the carpet. With the resistor in place, reconnect the battery and turn your key to on. If the code is no longer flashing, you may have a bad side airbag module. Don't panic and don't run out and spend all that money on a new airbag module yet! Turn the key off, disconnect the battery again, WAIT AT LEAST 1 MINUTE, AGAIN, and reconnect your connectors under the seat. Now, if you power up again and the code stays out, the connector was probably causing the high resistance reading and you don't need a new airbag. I just want to point this out because we are talking about a critical safety system here. There is a chance the airbag module is bad. If it continues to flash a code 37 after cleaning the connector, then you probably need to price a new airbag module.
Good luck with it.