Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
The problem is a bad ground at the taillights. When the turn signal or brake is used, these circuits try to pull a ground through the park light circuit, which also affects dash lighting. Check the black ground wire at the rear drivers side frame rail. If this ground is okay then the problem is in the bulb socket plates at the taillights . These are easily replaced and most parts stores keep them in stock (common problem).