ok i bought a 1995 chevy blazer and the heater core was busted and had to replace it. well me and my step dad replaced it and we got the dash andeverything put back but now my running lights wont work and also when i turn on my regular night lights it dings like when my door is opened but it isnt. and also my speedometer/tachometer stopped working. can anyone help me with this. this is my only source of transportation..... thanks

Check your fuses and your wire harness connections. Could be a ground connection. You have to go back and look over the wiring. A good schematic diagram could help back probe the wiring.