Brake lights stay on!!!! HELP

Rroop32 · Aug 26, 2013

Been having a problem with tail lights recently. Truck is a 05 QC 5.7 4x4. My issue is the brake lights randomly get stuck on all the lights including the 3rd light on the cab. I've been through 3 brake light switches and the issue keeps occuring. I have also reset the switches (even though they are 1 time use only) it happens atleast 3 times a month. What I've noticed is that when I disconnected the negative battery terminal for a few minutes and hook it back up, they work normally. I'm starting to think this is an ecu issue now. Any one else experienced this before or heard of this? Any one know what could possibly be causing this? I noticed tonight that when pressing the brake pedal and releasing the brake lights were delayed going off when I released the pedal and can hear a loud audible click from under the hood? Any one have any ideas?

HolyRamBatman · Aug 26, 2013

Welcome to RF.

Is there a relay in the fuse box under the hood for the brake lights?

Rroop32 · Aug 27, 2013

Didnt find a relay just fuses...nothing specifically pertains to the brake lamps just "tail lamps"

Sent from my SPH-L710 using Tapatalk 4

Rroop32 · Aug 28, 2013

Did it again last night. So for the hell of it ill put another switch it. A new switch went in last night and the lights were fine about 8pm. Came out this morning at 3.30am and my brake lights are stuck on.

Sent from my SPH-L710 using Tapatalk 4

Rroop32 · Aug 28, 2013

So I pulled the negative terminal on the battery and for a few minutes and now eveything works like it should. Any one else have or had this issue?

Sent from my SPH-L710 using Tapatalk 4

BigSloth · Aug 28, 2013

It's the relay, just gotta find it. The ECM has no bearing on brake light or any safety system operation in case of failure. If you can't find the relay by it's label, try doing it by having someone press the pedal while you listen and feel for which relay clicks. May take a few tries but figure out which one clicks and swap it With a known good one of similar build. Just borrow one from horn Or AC or something not crucial to engine operation.

It's either going to be a relay or the PDC corrosion problem, but let's start with relays.

Rroop32 · Aug 28, 2013

Update**

Bought an oem brake light switch though work for cost, but I haven't installed it yet.

However, I read the above post and started pulling relays. Nothing turned the brake lights off excpect #1 labeled "electric brake". I swapped it with the same #30 pink fuse from the ac blower spot and brake lights went out but then didn't function at all. So I swapped them back and the lights lit up again like they are stuck on. I then went under the dash and disconnected my trailer brake from its harness. Brake lights went out but wouldn't function again at all. Hooked the brake controller back up, and now lights perform normally.

fuse I pulled that made lights go out was the pink one very top left hand corner. Labeled "electric brake"

Sent from my SPH-L710 using Tapatalk 4

Rroop32 · Aug 28, 2013

Now with thw brake controller disconnected the brake lights don't work unless the truck is running. And the third brake light doesnt come on at all. I watched the bulb in the third brake light light up just a little bit then go off so ill let the rain die off and check the bulb.

Sent from my SPH-L710 using Tapatalk 4

Rroop32 · Aug 28, 2013

New bulb in and brake lights still don't work with truck off only when running. Brake contoller disconnected

Sent from my SPH-L710 using Tapatalk 4

Redtruck-VA · Aug 28, 2013

Looking at the 04 manual it looks very simple, Bat to IPM, fuse, switch, high mount brake light. The High Mount Brake light is a good indicator because it is a separate circuit from the rear brake light. The switch has three sets of contacts, High Brake light, Brake sensor to Instrument Cluster (cruise) and IPM to operate the rear brake lamps. Disconnecting the battery seems to be having some influence so I would look closely at grounds and IPM connections. Good luck..

Rroop32 · Aug 28, 2013

So far this is very frustrating. I tried disconnecting the battery like before and nothing changed.
With truck off and depressing brake pedal no lights are illuminated. With truck running rear brake lights are illuminated with the exception of the third brake light.

Sent from my SPH-L710 using Tapatalk 4

Redtruck-VA · Aug 28, 2013

Do you have corrosion in the third light that might be grounding that leg? Check the manual and do some research.
My Dodge: Dodge Owners Service Manuals - Dodge Cars, Minivans, SUVs

Rroop32 · Aug 29, 2013

As stated before I noticed a clicking from under the hood/dash. When I touched this cable under the dash I could feel the "click" in it. The cable runs from under the gauge panel through the connector pictured above and through the fire wall. Any ideas what this is. I'm going to take the knee bolster off and check grounds and wires along with the trAiler hook ups after work.

Sent from my SPH-L710 using Tapatalk 4

Rroop32 · Aug 29, 2013

May have figured it out. I read that the 4 pin connectors in the trailer hook up corrode, the looked pretty gross, so for the time being I cut it off and will splice a New one in shortly. Also found a blown fuse (that wasn't there before) for the brake controller. Replaced th fuse and disconnected the brake controller. Found the 2 day old brake light switch to have a sticky plunger and promptly replaced with another,

Now everything works. So something between the switch, brake controller ( since something blew the fuse with in the last 24 hours) and the 4pin.

Sent from my SPH-L710 using Tapatalk 4

Rroop32 · Sep 2, 2013

Brake lights have acted normal for a Few days now, hopefully it stays like this

Sent from my SPH-L710 using Tapatalk 4

ms8091 · Sep 2, 2013

I have had similar situations with brake lights and it has always lead back to a ground or the damn trailer wires. Good luck.

Sent from my iPhone using Tapatalk - now Free

M.A.D · Mar 7, 2016

I have an 03 dodge ram 1500. I'm also having problem with brake staying. Brake light stay with the switch is turn on or while the truck is run. But my 3rd brake light work fine. Just the two out by the tail gate. When, I turn the truck off, light goes off. Also since my brake light staying on, it's causing my cruise control not to work either. Have already replace brake light switch get that from the dealer ship, new bulbs & two light modular from dealer ship as well. Thinking it was my FCM. Replace that & till having this problem.

Redtruck-VA · Mar 7, 2016

The brake switch has three sets of contacts. 1 set is a brake sense to the PCM. 2 set third light brake. 3. goes to the CAB, FCM which then triggers relay for the IPM to provide 12v to the rear brake lights. Since you have changed the FCM I would guess you have some corrosion in the IPM not letting the brake lights function. I seem to remember and I may be wrong, but I think there is a default that lights when there is lost of PCM sense. If there is no corrosion in the IPM then I recheck the brake switch. Manual says the switch can only be installed once as it adjusts itself for plunger depth. Good luck..

Brake lights stay on!!!! HELP

Junior Member

Senior Member

Junior Member

Junior Member

Junior Member

Senior Member

Junior Member

Junior Member

Junior Member

Senior Member

Junior Member

Senior Member

Junior Member

Junior Member

Junior Member

Senior Member

Junior Member

Senior Member

Similar threads

Forum statistics

Share this page