Was in the car during a very slow, around 5mph front end collision. The knee airbag went off at low speed. I. Exited the vehicle to look at damage and then I sat back in the driver seat. Upon sitting back in the driver seat I noticed the smoke that had cleared from the airbag had started to build back up and became more dense. I had my feet outside the door while sitting in the driver seat and when I when I looked around I noticed a fire getting larger and larger from the pillar to my left, between the rear seat and the front driver seat. I didnât have anything to put it out so I tried to blow it out and it was getting larger and larger melting more of the plastic up the pillar. I ripped off a work shirt I had and was able to smother the fire with it. Had I not been able to smother it this fire would have engulfed the whole vehicle. After observing the damage the wiring harness had shorted out and burnt/ caught on fire that goes from the front of the vehicle to the back.there was no prior damage to the vehicle and no damage to the car other than the front end collision during the accident.