"Brake" warning light is on...why ?

[radeohedca]

I understand the warning lights normally come on when you turn on the car then go off a few seconds after the engine is started as a diagnostic check. They're just staying on.
I read on the Chevy Venture Forum that someone had problems with thier ABS lights coming on and they tracked it down to a short on one of the wires in the plug going to the rear light circuit boards. This afternoon I pull the lights off and checked the wiring and the "circuit boards" but found nothing wrong.

Whatever the problem, it's intermittent as twice today I got the van started with no lights illuminated.

I'll have to wait until tomorrow to try bleeding the brake systems. It's getting cold (my hands are numb), and I'll need to get some more brake fluid when the stores are open (closed for Good Friday).

Thanks, Hugh.

[1999montana]

Originally Posted by radeohedca

...How would bleeding the system correct things ? The lights are coming on right when I start the engine...the van hasn't even rolled yet so you would think it's not related to a wheel sensor....(

When you first turn the ignition key to run (not past the run position to start) the display that appears on the dash is called the 'proving circuit' test, meaning that it illuminates all of the indicators, and energizes all the gauges that normally appear on the dash panel.

It does this to allow for visual verification that all illumination (LED's, bulbs, etc) and all gauges are working properly and receiving power.

Hope this clarification helps.

[radeohedca]

Yes, I understand that the warning lights on the dash all illuminate as a "Lamp Test" when you first turn on the car.
I was saying that the warning lights come on and stay on (past the diagnostic test period) before the van even moves, as opposed to coming on after the van starts rolling and the computer detects a mismatch in wheel rotation speed to trigger an ABS event.

I think we're getting offtrack here. I need to figure out why the ABS/TCS and Brake lights are staying on.

[1999montana]

Originally Posted by 1999montana

....Could be a wheel sensor or the ABS, but mostly likely is not....

That would have only held true if the ABS light were not on in the first place.

I think you may have pretty much begun to diagnose your own problem, particulary since you mentioned afterwards that the ABS light was on for some time "...Okay, <blush> I neglected to mention that the ABS warning light has been on for a couple of months. I suspect a bad wheel bearing and was waiting for the warmer weather to change it..."

Until you eliminate this obvious root cause, (the wheel sensor or connector generating a bad return voltage), you may not be able to go much further in figuring out why the brake warning light is on solid.

As unlikely as it might sound, it could even be one of the circuit boards in the rear taillights giving you trouble. The sockets burn and short out. This also generates a series of other failures that seem unrelated.

If it were my van, I wouldn't be driving it at all, or putting my wife or kids in it until I knew what it was, and then I'd probably pull the van off the road and fix it.

A two metric ton vehicle is no fun to drive if you can't stop it! And while you may be able to stop right now, the light may just be the beginning of something that may lead in a direction you don't want to go.

Your choice of course, but what about anyone else that might get hurt while you wait for warm weather to 'fix' it?

[radeohedca]

Originally Posted by 1999montana

As unlikely as it might sound, it could even be one of the circuit boards in the rear taillights giving you trouble. The sockets burn and short out. This also generates a series of other failures that seem unrelated.

I read about this on the Chevy Venture Forum so I already investigated it the other day. I removed and disassembled both Lamp assemblies. No sign of shorts on the wiring harnesses or "circuit boards", visually nor by ohm meter check.

If it were my van, I wouldn't be driving it at all, or putting my wife or kids in it until I knew what it was, and then I'd probably pull the van off the road and fix it.

Agreed. That's why I'm all over this but it seems like a more complex problem that's beyond us "backyard mechanics". I've exhausted the obvious and every other thing that's been suggested so I'm getting close to just bringing it into the shop.

[1999montana]

Originally Posted by radeohedca

I read about this on the Chevy Venture Forum so I already investigated it the other day. I removed and disassembled both Lamp assemblies. No sign of shorts on the wiring harnesses or "circuit boards", visually nor by ohm meter check.

Agreed. That's why I'm all over this but it seems like a more complex problem that's beyond us "backyard mechanics". I've exhausted the obvious and every other thing that's been suggested so I'm getting close to just bringing it into the shop.

Hugh,

I know your frustration.

This and other forum sub sets, are a great place to share experience and trade ideas, but this venue is not the best place to come to get your van 'fixed'.

Opinion causes people to think and I like the way this forum presents a number of sides to a given problem. Often viewing something from a different angle forces one to look at it a little differently.

On the downside however, the number of knowledgeable folks fluctuates from a few, to many depending on who owns what type of vehicle and how experienced they are at finding their way around it.

That said, I don't think it would surprise anyone that the likelihood of 'pushing' a problem until someone comes up with the solution is likely less than 10%, despite the number of viewers or contributors.

While the solution once found may seem like an obvious one, there are far worse choices one can make than letting an experienced and trusted tech look at it.

[radeohedca]

I tried to troubleshoot to the best of my ability but I do recognize my limits and am quite willing to "pay the man" once I've given myself the chance to exhaust the obvious. My youthful days of relentless stubbornness are well behind me

I took the van in to a local shop today and they tell me the ECBM is intermittent. $500 for the part and a couple of hours labor to replace it and bleed the complete system. The part had to be ordered so I have to bring the van back in tomorrow.

BTW, my only frustration was with the lack of DTCs when I did an OBD2 scan (with 2 different units). I know that there's something wrong with the ABS and possibly a secondary problem with the base breaking system...What do you mean there's no DTCs ? Of course the mechanic's scantool detected some error codes so it would seem these consumer handheld OBD2 scanners are worthless for anything beyond basic diagnostics.

Hugh

[gwicken]

I have had the same problem several times to fix the problem I've changed the front brake pads and the lights all go off. If you haven't replaced in a while it might be worth a try. usually the pads aren't all that bad looking but the lights go off for me.