I'll just add, to fix the "fast flash" after splicing in the trailer wires and hooking up the traier, you need "heavy duty" turn signal and flasher units. They are avaialble at any autoparts store for $5-10. They will plug in to the harness under the dash. They look like a small round can. To find them, you can activate the turn signals or flashers and trace the sound they make.

The only drawback of the "heavy duty" units is they won't warn you if a bulb is out by a "slow flash". As long as you check your lights from time to time, no problem.