Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Brake Lights & Parking Lights Both Go On

1999 NISSAN Sentra GXE: When I press the brake pedal, both the brake lights and the front parking (running) lights go on. All go off when the brake pedal is released. Very strange problem I’ve never seen before…thank you.

This problem is often caused by a defective dual filament bulb in the rear lights. When you press the brake pedal, the brake light filament makes contact with the tail light filament. This then powers the parking lights in the front. Replace the rear bulbs and you will most likely solve the problem. If this doesn’t solve the problem, then there is a cross connection someplace in the wiring other than a bulb. Do you have a wiring harness for a trailer?

No wiring harness for a hitch. I’ll try replacing the rear blubs as the initial step and hope that solves it. Thank you for your help as I had no idea where to begin with something like this.

You could also have a bad ground circuit back there. Check the ground wire for corrosion or breakage. A multimeter can tell you in an instant if the ground circuit is open. Then, the brake light will seek ground through the parking light circuit, powering both circuits.

Sometimes this happens when someone changes a bad bulb that has dual contacts and replaces it with the wrong bulb that has a single contact, which bridges (shorts between) connectors in the socket causing weird stuff like this.

Did you recently replace any burned out bulbs?

Replaced both rear light bulbs and the problem was solved. The two contact points on the bottom of each bulb were flatened/ compressed (likely due to age) and touching.
Thank you all again for your help!