Brake Problem Question

[FastRam]

My 2006 RC has been having a problem with the brakes, specifically with the "brake" light illuminating. I was having a problem with the parking brake not releasing fully, which caused the brake light to flash when the vehicle moved. My dealer replaced the brake switch and adjusted/lubed the parking brake release. Now, over the past 4 or so days, the brake light has been coming on while the vehicle is in motion, well after the parking brake has been released. When the light illuminates I hear two chimes from the dash.

The brakes themselves still grab and stop the vehicle as they always have. The ABS light does not illuminate only the brake light. I checked the master cylinder fluid and it was less than 1/4" below the max fill mark, so I topped it off with new DOT 3 fluid. I checked the wiring connector at the master cylinder and it was tight, no corrossion, etc. I checked the calipers and lines and could not find any leaks either.

My dealer's Viper tech I use is booked until Aug 3rd. I have an appointment scheduled for then but is there anything else I can check in the mean time? My concern is one time the light will come on and the brakes will actually be failed when I would need them to work...

 

[JTS VENOM PERFORMANCE]

sounds like the park brake may be adjusted to tight, under the cab you can adjust it and loosen it from there, but also you may need to remove the rear rims, and rotors an inspect the park brake assembly, make sure one the shoes are not worn, two, that they are adjusted correctly, they could be slef adjusting and causing them to get tight an burn the shoes to quickly

 

[BLWNSRT]

I haven't had the drum ebrake assembly apart on my srt but I know on the chevs and fords they have a cam that is pulled to apply the brakes and if they stick or are seized it will cause problems. If you can take the rotors off you can use a prybar or get someone to apply the ebrake and see if it releases fully.

 

[FastRam]

Thanks guys. But, if the e brake isn't released fully or is hung up at the rear calipers, wouldn't the brake light flash when I first try and move the vehicle? That is what happened several weeks ago. Now, the light comes on when I'm going down the road, well after the e-brake was released. As an example this morning I left my house for work at 5:30AM. I was on I-95N by 6:00AM, travelling 70 mph (or so) and half way to my destination the dash chimed out and the brake light illuminated. It did the same thing every day this week going to and from work. When the light comes on it is solid on, no flashing. FYI: when I turn the engine off and let the truck sit for a few minutes, start it back up, the brake light stays off. Start driving it again and some random time later, the light comes back on.

 

[NickGuyver]

I came on today to post that as of last night this has happened to me 4 times since last night. I have a QC and my ((ABS)) light is also coming on. Other than that it's identical symptoms, no DTCs or anything else. I also never use my parking brake...

Also, I live just south of DC, where is the Viper tech you are talking about?

 

[FastRam]

I came on today to post that as of last night this has happened to me 4 times since last night. I have a QC and my ((ABS)) light is also coming on. Other than that it's identical symptoms, no DTCs or anything else. I also never use my parking brake...

Also, I live just south of DC, where is the Viper tech you are talking about?

Jeff over at Safford Dodge in Springfield, VA. He already replaced the brake light switch and adjusted the parking brake mechanism inside the cab and went through the complete system, brake lines, calipers, pads, parking brake, etc., basically a complete inspection, they found nada at the time they completed this, work (about three weeks ago). I was out of town last week and this week, driving the truck, the "lighting" problem started again... I'm going to check the service manual - I'm wondering if a sensor or some controller/module is going south???

Maybe the brake issues are chronic to the Washington DC region, friggin traffic sucks around here and it's been hotter than Hades to boot...:dontknow:

 

[FastRam]

I just went through the 06 service manual,. There are several tests that can be performed without the use of DRB III (scan tool). Several sensors and components can cause the brake light indicator to become INOP. These parts include the brake fluid level sensor, parking brake switch (which I had replaced under warranty), the anti brake module and the instrument cluster. I have my Tektronix O'scope on battery charge. Hopefully this weekend I can trace this one down. More to follow...

 

[NickGuyver]

Awesome, keep me posted on what you find out.

 

[FastRam]

I just got done poking and prodding with my meter and jumpering out some wiring terminals. First I was very pleased not to burn up any thing or blow any fuses, lol....

After disconnecting the neg batt lead, I jumpered the park brake switch sensing circuit to ground, reconnected the neg batt lead and turned the ignition on. Brake light did not illuminate. Unfortunately I didn't check for any open circuit with the brake switch -- this required pulling the instrument cluster and a connector on the back of the cluster -- C3. I didn't want to get into pulling the cluster out from the dash. So, the new brake switch I had installed or the wiring being defective is inconclusive.

Next I moved to the brake fluid level sensor. Disconnect the neg batt lead, and jumpered out pins one and two of the wiring connector, reconnected the neg batt lead, turned ignition on . Brake light did not illuminate. OK, next step -- I measured the resistance between ground and the level sensor circuit ground, pin two of the connector. Resistance was less than the manual's specified 5 ohm threshold. No open ground circuit -- good. Next I was going to check for an open on the sensing circuit. You do this by measuring resistance between pin 1 of the brake fluid level connector and pin 11 of the anti-lock brake module connector, C1. I decided not to fool with the anti-lock module. I felt this is where I could really screw something up so I left it alone. But if one wanted to, the anti-lock brake connector needs to be disconnected and resistance is measured between terminal points noted above. Again, you're looking for a measured resistance below 5 ohms. Fluid level sensor or wring being defective is inconclusive.

And finally, I couldn't check whether or not the instrument cluster was good -- for that you need the scan tool.

Some caution notes.

1. If you're not familar with or comfortable working around vehicle wirng systems, do not attempt any of this.

2. I undertook this effort using the 2006 service manual and the wiring diagrams and trouble shooting processes. I am not sure if these are applicable to 2004/2005 model years. Use the correct manual for your year.

3. Be very careful when inserting jumper wires or jamming test leads into the connector bodies. The holes are small and you can easily damage the terminal or connector body if too large of a wire or test lead is inserted. I used #18AWG stranded wire.

4. Before disconnecting and reconnecting any connectors, jumper wires, etc. disconnect the neg batt lead and then reconnect it only after you double check everything.

I guess had some success but it looks like I wait for Aug 3rd to role around to get this problem sorted out fully. But, what's even stranger now, this past Friday and yesterday, the brake light did not illuminate at all while driving around. Parking brake release and the brake light operation when the parking brake was applied and released was fine, no problems at all.

 

[FastRam]

As a follow up, today I took my truck to the dealer for the brake issue and to finally replace the power steering pump and pulley. PS pump and pulley, done. Brakes -- that requires a new fluid reservoir and level sensor. When they connected the scan tool, a fault code appeared that pointed towards a defective fluid level sensor. And of course on the 06 (not sure about other years), the level sensor is serviced with the reservoir, can't do one without the other. So, Friday back to the dealer she goes.

 

[Brat]

Good to hear you got it figured out.

 

[AZBLACKMONSOON]

My 06 Quad cab is doing the same thing. Brake light will turn on, randomly . I will look at the sensor and wire connections.