SSTraveler,
Do you have the OEM installed factory towing package?
If so, it follows the generally accepted USA standard 7 way round wiring schematics.
You should be able to buy a 4 pin conversion plug at your local auto parts store and
simply plug it into the 7 way, then plug your 4 pin trailer connector into the adapter.
In the same display area they have little LED circuit testers that are wired to the same
conventions and schematics.
Reese Towpower 7-Way Round to 4-Way Flat Adapter
Model # 74607 Internet # 202282286
Store SKU # 150745
< $10.00
Hope this helps,
Roger