2006 Toyota Tacoma electrical system problems

My cigarette lighter popped out of its receptacle on to the floor of my brand new truck (approx. 4,000 miles) causing a fire that destroyed 75% of the interior. Twenty minutes after the fire was put out I called the dealer that I bought the truck from. They told me it was a manufacturing issue and offered no help. Toyota sent an investigator to inspect the truck and he did just that, for about 4 hours. Eventually they sent a letter to me (2 months later) that suggested an outside source could have started the fire.

As the weather increases above 85 to 90 degrees the directional signal and the hazard flashers cease working. Once the operation of the vehicle has ceased and the temperature and the vehicle cool down normal function returns. I believe the problem is in the engine compartment because when using the A/C in the cab the cool air has no effect. This is a safety hazard because I do not know when it will occur. Leaving me without signals while driving.