I was having all kinds of problems with my truck over heating, and not blowing warm air. Finally after replacing the water pump, thermostat, radiator and hoses it stopped over heating but the heat was still not warm. So I take it to a shop and they run some tests and it needed a new heater core. So they put the heater core in and I get the truck back and notice now the blinkers, and lights on the truck dont work right. When I press the brake my dash lights light up, when I turn the blinker on both back blinkers flash, when I turn the headlights on the blinkers dont work at all and the third brake light on the back of my cab comes on. I call them and they tell me that them changing the heater core couldnt have caused any of that, but everything was fine and working normal before they changed the heater core. What should I do next and what in the world could have caused this by them changing a heater core.... any ideas or what I should do next....

 

Call them back. It worked fine before, now its screwed up. They have to remove the dash to change the heater core, and guess where the wiring for ALL of those circuits are? Yep, you guessed it, IN THE DASH. If they refuse to even look at it (for free.... their fault after all....) let them know your next call will be to the better business bureau. Or your lawyer......