Ok. I'm sorry for the long post, but I'm absolutely lost as to what the problem may be... About 2 weeks ago, I got the typical Brake Light Switch Failure symptoms. I immediately ordered a new part, and installed it, with no luck. I ordered a second replacement thinking the switch may have been bad out of the box. Still no luck...

The issue springs up in the weirdest situations... Despite replacing the switch, the 3rd brake light always stays illuminated, and when the DRLs are on, one of the brake lights works intermittently. If I leave my lights in automatic, and it is light out, I can drive around endlessly without the dash lighting up like a Christmas tree...

However, if the headlights are on, the third dbrake light stays illuminated and the brake lights do not work. If I drive around while touching the brakes every 20-30 seconds or so, no warnings will ever come up. However, If I drive for 4-5 minutes straight, and don't have to use the brakes, the issue pops up again. It says HDC inoperable, the brake light comes on, a transmission fault warning pops up, and the suspension lowers. If I turn off the vehicle, and restart, the issue goes away for a few minutes, but will pop up again. After the restart, there are still no brake lights, etc. I have replaced all of the taillight bulbs with LR specific bulbs, and I've replaced the brake light switch 3 times. I have also cleared all of the codes from the ECU and started over, and it still happens.

Any ideas? I really can't afford to go through a stealership to get this fixed. Also, why do the warnings only appear when I avoid using the brake pedal? I just spent $1800 fixing this stupid vehicle last month, and now all of this pops up! Somebody please help!!!

 

The wrong lamps are a possibility. Make sure you dont have brakes lamps in all four locations, brakes are just one on each side. However, I dont think that would cause these issues.

So do you or did you have any water entry issues, basically are the footwells damp/wet? If so you could have water damage to the central junction box behind the passenger glove box. Have you tried things with one lamp removed at a time? While you may get a warning, maybe removing lamps would narrow things down by basically disconnected that specific circuit. If there is still an issue with the third light, then I would certainly start to think its a wiring issue.

 

Thanks for the ideas. There hasn't been any leaking/water issues. I checked all of the lamps, and they were all the correct type and in the correct places... I'm wondering why a specific drive cycle has to complete in order for this to happen...

 

Well honestly there are a couple things that can trip these faults, but the kicker is that third light. That tends to make me think its wiring related somehow. I would still pull lamps or even one entire rear lamp assembly at a time and see what the third lamp does. Even with a ton of faults, the brakes lights at a basic level should work as intended.

 

Same makes me think there is corroded connection or a pair of wires crushed/crossed together

 

That third light comes down via the LH side where the trailer connections are, have a look there

 

Thanks for all the suggestions. Would a crroded wire cause all of the warning lights on the dash? This all started at the same time.