The rear taillights stay on when I shut the car off?

Tiny
CARY_JAY
  • MEMBER
  • 2005 CHEVROLET IMPALA
  • 3.8L
  • V6
  • TURBO
  • 2WD
  • AUTOMATIC
  • 215,000 MILES
I have changed the ignition switch, the hazard switch, and the brake light switch and also the light switch and they are still on, initially when this happened I noticed that they were on after I shut the car off and it drained the battery, it wouldn't start and my gas gauge said empty and my lights were flashing no fuel and security and service vehicle, (not the check engine light) in addition the starter didn't click when I tried to jump start it. I had almost a full tank of gas, so I knew the fuel pump and starter didn't fail at the same time. I was able to touch the battery terminals together and drain the capacitors in the computer and I was able to clear it out and it restarted and ran normal, except the tail lights don't shut off when I turn the car off. They are even on during the day. What is confusing is when I brake, the light gets brighter. So I'm thinking the brake switch works, even thou I replaced it, so it's like the tail lights. Intensity is on all the time. The confusing part is the center, cyclops brake light is on too. Any clue what this could be? A bad ground? I could see if they didn't turn on. But not shutting off? Do you think it could be a bad circuit in the body control module.I'm suspecting it might be, because of the security issues I initially had, before I cleared the computer. Could someone scan the car and find the problem?
Wednesday, March 29th, 2023 AT 9:56 PM

21 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
I would remove the rear brake and running light bulbs to see if you have melted sockets or terminals. please check out this guide:

https://www.2carpros.com/articles/no-tail-lights-exterior-running-lights-tail-lights-out

Also, it sounds like the running light control relay is stuck on here is the location on the right side of the dash so you can swap it out which should fix the problem with the lights staying on. Also, here are the running light wiring diagrams so you can see how the system works. Check out the images (below). Please let us know what happens.
Images (Click to make bigger)
Thumb
Thumb
Thumb
Was this
answer
helpful?
Yes
No
Thursday, March 30th, 2023 AT 12:04 PM
Tiny
CARY_JAY
  • MEMBER
  • 17 POSTS
Thanks, I have been thinking about the relay today, I actually pulled out all the fuses and the parking light relay and it was still on, I have not checked the sockets yet, because the lights are turn signal still work, but the new hazard switch I put in seems to blink fast. So I will check that. I noticed that there are 2 different circuits for the front parking light and the back, I did notice when I changed the headlamp switch that it looked like the brown/white wire might have got a bit hot.I had a bad hazard switch for a while and would jiggle it on and off to get it unstuck before I replaced it.I suppose that could have shorted out something.I guess I don't have a problem with the front parking lights staying on, but maybe other things with the headlight switch turn them off.I think that connection is always hot if I'm reading the diagram right, so it could be the contacts are welded together or stuck, so it won't shut off.I was thinking the brake switch or circuit, because the center rear light was on.I would think if it was the parking lights, that shouldn't be on. But I will try both of those suggestions. And get back to you. Thanks
Was this
answer
helpful?
Yes
No
Thursday, March 30th, 2023 AT 12:34 PM
Tiny
CARY_JAY
  • MEMBER
  • 17 POSTS
Thanks for the diagram that actually includes the rear taillights, I have been looking all over for one that actually included that.
Was this
answer
helpful?
Yes
No
Thursday, March 30th, 2023 AT 12:44 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
The only other thing I can think of is the hazard switch because there is logic control which is integrated into the switch that might be bad. Only remove the bulbs to make sure you don't find a bulb contact melted. Here is how you can check out the hazard switch in the images below. Please let us know what happens.
Images (Click to make bigger)
Thumb
Thumb
Was this
answer
helpful?
Yes
No
Friday, March 31st, 2023 AT 10:33 AM
Tiny
CARY_JAY
  • MEMBER
  • 17 POSTS
I actually replaced the Hazzard switch with a new one, the old one was actually bad, before I had all these problems, the turn signals would freeze up on me, I actually think a short in this switch caused the other problems, I am going to check out your suggestions this weekend I hope, big winter storm on the way, I'm thinking I should just be able to swap relays with the back up or battery drain relay. To see if that is bad, otherwise I'm going to check the bulbs to make sure filament are not broken off and touching or bad bulbs or corrosion or oxidizing. Sockets, as well as the ground connection.I was also wondering about a ground connection that is by the passenger door, by the ' A' pillar? Is that under the trim inside the car? By the seatbelt do you know?
Was this
answer
helpful?
Yes
No
Friday, March 31st, 2023 AT 10:53 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Yes, the ground is by the door pillar, also I would recheck the hazard switch you may have gotten a defective one.
Was this
answer
helpful?
Yes
No
Sunday, April 2nd, 2023 AT 9:39 AM
Tiny
CARY_JAY
  • MEMBER
  • 17 POSTS
Well, I tried to swap out the relay with another one next to it and it was still on, so it probably isn't that, I will check out the actual tail light assembly this week, just had a snow storm and I don't have a garage, so I'm waiting for the weather to get a bit nice, I'll try another hazard switch, to see if that is it, the one I replaced the bad one way blink's a little fast. If it isn't any of those do you think the could be a circuit in the BCM that went bad? I'm just wondering if that might be the problem, because I had to reset it, after this happened, it fixed the other issues I had with the car starting, of its the BCM, that is a little beyond the scope of what I can do, I would think you would need a scanner. Initially when this all happened with the security light and the low fuel and the service vehicle soon light flashing I was unable to connect with a 0BD2 scanner, but now I can with the reboot, but no video reading.
Was this
answer
helpful?
Yes
No
Sunday, April 2nd, 2023 AT 4:00 PM
Tiny
CARY_JAY
  • MEMBER
  • 17 POSTS
Do you know if there is a brake switch stopper on the brake that might have come off? I replaced the switch, but maybe it needs to be adjusted, the brakes do get brighter when I step on them, so it confuses me as to why the 3rd brake light is one with the running lights. You think that would be off. The fact they are on during the day top. Tells me it's the brakes. Do you think it could be an issue with the abs/ traction control module?
Was this
answer
helpful?
Yes
No
Sunday, April 2nd, 2023 AT 8:42 PM
Tiny
CARY_JAY
  • MEMBER
  • 17 POSTS
Or I wonder if I should try and adjust the brake control switch, I should try and push it all the way in manually and have someone stand behind the car and see if that turns them off.I know on some cars they have a rubber stopper on the brake pedal that engages the switch. And it deteriorated or falls off. I think this switch just makes contact with the steel.
Was this
answer
helpful?
Yes
No
Sunday, April 2nd, 2023 AT 8:46 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
I don't see a BCM in the system if you look at the wiring diagrams above you can see there is no BCM, can you try unplugging the brake light switch to see if the lights go out?
Was this
answer
helpful?
Yes
No
Monday, April 3rd, 2023 AT 10:55 AM
Tiny
CARY_JAY
  • MEMBER
  • 17 POSTS
I see the BCM, it feeds into the headline and the relay, 2nd component down on the upper right.
Was this
answer
helpful?
Yes
No
Monday, April 3rd, 2023 AT 2:20 PM
Tiny
CARY_JAY
  • MEMBER
  • 17 POSTS
I thought it all went through the body control module these days, because it's all integrated. As far as daytime running lights and all that.I could be wrong. I guess I'm not sure what caused the computer problem I had when I first noticed the lights were on, when I got off work at night. The car ran fine when I drove it to work and shut it off.
Was this
answer
helpful?
Yes
No
Monday, April 3rd, 2023 AT 2:24 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
It does but that would make all of the running lights stay on not just the rear unless the fuse is blown for the front lights. If the BCM is in question you can get a CAN scanner (Controller Area Network) from Amazon.

Here is a video to show you how:

https://youtu.be/u-4syLc-ifQ

and

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Here is one for about $99.00 if you need it:

https://amzn.to/3ZixY4v

This will tell you if the BCM is bad.
Was this
answer
helpful?
Yes
No
Tuesday, April 4th, 2023 AT 9:41 AM
Tiny
CARY_JAY
  • MEMBER
  • 17 POSTS
Ken, I'm going to take a look at it this weekend, it is finally going to be sunny and in the 60s here in Minnesota this weekend, I don't have a garage and the weather has not been good. I printed the 2 wiring diagrams and
taped them together so I could look at the "big picture ". The center high mounted stop lamp stays on. And the two on the sides. Looking at the diagram, it has to be the brake switch circuit or the hazard switch, the wiring or the ground.I don't think it is the running lights, they are not even on the same circuit, from what I can see. The lights do get brighter when I step on the brake, so I am going to try and adjust the brake switch and see what that does with a helper looking at it as far as if it shuts off when I disconnect it or when manually pushing it in. And check all the grounds and light socket connections. I'll get back to you. What is the component on the wiring diagram that is right below the stop lamp switch is that a relay? Could that be the problem? There is some.
Was this
answer
helpful?
Yes
No
Thursday, April 6th, 2023 AT 1:03 PM
Tiny
CARY_JAY
  • MEMBER
  • 17 POSTS
What is the name of that relay? I noticed there is something plugged in on the back of the fuse terminal on the driver's side, not sure what that is.
Was this
answer
helpful?
Yes
No
Thursday, April 6th, 2023 AT 1:04 PM
Tiny
CARY_JAY
  • MEMBER
  • 17 POSTS
So, I just tried to screw the brake light switch in all the way and it was still on, then I completely disconnected it and all 3 rear lights were still on. It must be drawing power from somewhere else, which would be the hazard switch. So I will try and replace that again with another one to see if I got a bad one, if it isn't that it has to be a bad ground or socket or BMC.
Was this
answer
helpful?
Yes
No
Thursday, April 6th, 2023 AT 2:36 PM
Tiny
CARY_JAY
  • MEMBER
  • 17 POSTS
The only other place it could be getting power would be from the Hazard switch, if I removed the brake switch, the only thing I haven't replaced is the turn signal / multi function switch.I'm not sure if that could be it, I did notice that with the keys removed if I flipped the turn signal lever I was getting feedback. ( Buzzing) thru the hazard switch.I'm not sure if it is supposed to do that. Or if it should do nothing.
Was this
answer
helpful?
Yes
No
Thursday, April 6th, 2023 AT 3:08 PM
Tiny
CARY_JAY
  • MEMBER
  • 17 POSTS
I have actually been reading this pt cruiser forum in which this turn signal/ multi function switch has created similar problems of running lights or fog lights not shutting off when the car is turned off and draining the battery. Maybe that is the culprit.
Was this
answer
helpful?
Yes
No
Thursday, April 6th, 2023 AT 3:58 PM
Tiny
CARY_JAY
  • MEMBER
  • 17 POSTS
Thanks for the help Ken, I'm thinking it was the Body control module, my lights starting going off, the airbag, the security light, all my gauges went dead, the radio was turning off and on.I was disconnecting the battery and driving it while I was trying to figure out what it was, unfortunately it doesn't matter now.
Images (Click to make bigger)
Thumb
Thumb
Was this
answer
helpful?
Yes
No
Wednesday, April 12th, 2023 AT 2:29 PM
Tiny
CARY_JAY
  • MEMBER
  • 17 POSTS
I believe that a short in the abs/traction control module started this, when this initially happened, I noticed what looked like light smoke on the electrical connectors when I lifted the hood, it was pretty cold that day. Although I didn't notice again after I cleared the computer and got it started again. It appears to have started in the same location as it, looking at where most of the fire damage is on the right side, and after looking at the fuse box diagram, it looks like the brake switch is located on the same circuit.
Was this
answer
helpful?
Yes
No
Thursday, April 13th, 2023 AT 8:37 AM

Please login or register to post a reply.

Related Running Light Stay On Content

VIEW MORE