99 Sephia - Rear Brake Lights Always On

[dnissley]

I'm really stumped on this one...

My rear brake lights are always on when the car is on, and pressing on the brakes does nothing to change that. The third brake light works properly though. All turn signals work properly. All lamps work properly. The rear brake lights DO turn off when the car is off.

I switched out the brake light switch, thinking that it might be faulty, but it didn't change anything. Changed the bulbs too, but no change. What the heck's going on here? What should I check next?

[DavesSpectra]

Any trailer wiring?? The adapter modules go bad...
If there are large electrical connectors hidden behind the left plastic foot "kicK" panel (by the floor) you might look for water (corrosion) problems inside the plugs and connectors.
Water getting inside them can cause metallic corrosion similar to what is found when you electroplate something and causing lots of strange electrical/wiring problems. I have seen in KIAs that this is a common place for connections.

You may have to follow the wiring harness from the brake lights towards the passenger cabin and look for any damage allowing wires to short together..

In newer KIAs the BCM (body control module) has it's "hands" on the tail light wiring and an internal failure "could" cause this also. With it being a 1999 this may not be the case.

Just some thoughts...
Dave

[cobra259]

Could be a bad brake pedal switch.

[1fastkia]

Just change ANY bulbs? If you did I think you used an 1156 in a 1157 slot or vise versa.

This will cause this issue.

[biggermdc]

Originally Posted by dnissley

I'm really stumped on this one...

My rear brake lights are always on when the car is on, and pressing on the brakes does nothing to change that. The third brake light works properly though. All turn signals work properly. All lamps work properly. The rear brake lights DO turn off when the car is off.

I switched out the brake light switch, thinking that it might be faulty, but it didn't change anything. Changed the bulbs too, but no change. What the heck's going on here? What should I check next?

hope you sorted your issue out, but just a quick thanks as you post pointed me in the right direction to sorting out mine, it was a bulb it had half blown and was touching the second element in the bulb casusing a short, I had to look closly as you could just see it