2000 silverado brake light issue

[85square]

Recently my truck has been throwing the brake light on occasionally. Sometimes it will be on, other times it won't come on at all. It seems completely random. I'll go start the truck and the light will come on and stay on or it won't come on at all. It is the emergency brake light not the ABS light, however my abs light has been on for a while now due to a bad wire. I've looked all over the internet and cannot seem to find an answer. Its still pretty cold and snowy where i am so i have yet to jump into it. The reservoir is full of brake fluid and my brakes feel normal. I replaced my pads rotors and rear calipers about a year ago.

Thanks for the help!

[izzy_Britton]

so just for clarification, your ABS light is always on and your BRAKE light is intermittenet for no apparent reason? or does it happen that your ABS light is also intermittent?

you mention that there is a bad wire somewhere ? what is the bad wire that you know of?

There is a known issue with the 99-06 trucks that may be an issue on the older and/or newer trucks. anyways that issue is that the ABS pump/module grounding wire/strap under the truck on the frame rail nearest the module is known to be a bad connection.

I only mention this because i too have this issue however my issue is that BOTH the ABS and BRAKE light are intermittent together, both at the same time but never one at a time. after much research i have found the wire being an issue and cleaning and reconnecting the wire and grounding post seems to be the solution but i havent had time as of late to dig into it to see if it will fix my problem... YET.

I now have 4 of these 99-06 trucks and they ALL have the same ABS and BRAKE light issue. so i think that there is something to be said about the ground wire/strap on the frame. worth looking into anyways.

-Izzy

[85square]

Originally Posted by izzy_Britton

so just for clarification, your ABS light is always on and your BRAKE light is intermittenet for no apparent reason? or does it happen that your ABS light is also intermittent?

you mention that there is a bad wire somewhere ? what is the bad wire that you know of?

There is a known issue with the 99-06 trucks that may be an issue on the older and/or newer trucks. anyways that issue is that the ABS pump/module grounding wire/strap under the truck on the frame rail nearest the module is known to be a bad connection.

I only mention this because i too have this issue however my issue is that BOTH the ABS and BRAKE light are intermittent together, both at the same time but never one at a time. after much research i have found the wire being an issue and cleaning and reconnecting the wire and grounding post seems to be the solution but i havent had time as of late to dig into it to see if it will fix my problem... YET.

I now have 4 of these 99-06 trucks and they ALL have the same ABS and BRAKE light issue. so i think that there is something to be said about the ground wire/strap on the frame. worth looking into anyways.

-Izzy

Thanks I'll check that out. The lights aren't intermittent. A while back id be driving the truck and come to a stop when all of the sudden the abs would kick in. I replaced a wheel bearing and the abs issue continued. My issue was the abs wire that connects to the hub assembly.

[95 S_Trucker]

Have someone scan the ABS system for codes.

My guess is you'll have an EBCM Relay circuit code. C0265, and possibly some communication codes.

If you have those codes, you'll need to check the ground.

I've seen the ground issue, but I've also seen a bunch of bad EBCMs.



Also, check the brake fluid level, there is a sensor in the reservoir that will turn the red brake light on when the brake fluid is low. If the fluid is low, check the steel brake lines. They rust out on these trucks. Sometimes its a pinhole, other times it can be catastrophic.

[izzy_Britton]

Originally Posted by 95 S_Trucker

Have someone scan the ABS system for codes.

My guess is you'll have an EBCM Relay circuit code. C0265, and possibly some communication codes.

If you have those codes, you'll need to check the ground.

YEAH! thats the code/condition i was referring to. I just couldnt remember the code number.

Originally Posted by 95 S_Trucker

Also, check the brake fluid level, there is a sensor in the reservoir that will turn the red brake light on when the brake fluid is low. If the fluid is low, check the steel brake lines. They rust out on these trucks. Sometimes its a pinhole, other times it can be catastrophic.

he did state that the reservoir is full, which is why i was leaning toward the ground.

I am new to these trucks and so i havent even fixed my grounding issue yet. I am ever hopeful that the issue is the ground and not a BAD EBCM. the ABS module where i would assume the EBCM is located appears to be a major PITA to replace.

-Izzy

[95 S_Trucker]

The EBCM(electronic brake control module) is mounted to the EHCU(Electro-Hydraulic Control Unit).

The EHCU houses the valves. The EBCM tells activates the valves.

Replacing the module is the easy part. The module is expensive and needs programmed.

[izzy_Britton]

Originally Posted by 95 S_Trucker

The EBCM(electronic brake control module) is mounted to the EHCU(Electro-Hydraulic Control Unit).

The EHCU houses the valves. The EBCM tells activates the valves.

Replacing the module is the easy part. The module is expensive and needs programmed.

I dont mean to hijack this guys thread but in the interest of info for all i am willing to continue the discussion.

I was doing some research on the EBCM while you were responding to my last post apparently. I was mistaken in thinking that the entire unit EHCU and EBCM together was something that needed to be replaced together. i see now that the EBCM simply unbolts. that is really good to know.

the bad thing is as you mentioned that the EBCM is quite expensive. 2x+ more than i paid for the entire truck.

I didnt realized they needed to be reprogrammed. who or how is that done? dealer only or can a guy with a good scan/diagnostic tool reprogram one?

and i noticed that there is a lot of info on the web about the circuit board in the EBCM having some bad solder joints. it looks like these solder joints are an easy fix for someone handy with a solder gun. is this your experience? or do you have any inexperience with these?

-Izzy

[95 S_Trucker]

It can be programmed by any gm dealer. Usually a $50-$100 fee in this area. I have a good scanner and it cannot do it. The module needs to know the tire size and the axle ratio.

I haven't done anything with solder joints. I run a small independent shop. I do repairs that I have to warrant. I cant warrant a experimental solder repair, but it is something I would try on my own truck, just not something I would want to try on a customers car.

I have replaced several modules, on these GMT800 trucks, S10/Blazers, and a few uplander minivans.

[Flying Hamster]

O.P. says he's in New York... Rust Belt.
As am I. Mine does the A.B.S. light game every spring. Little bits of rust get on the magnet for the A.B.S. sensor and give it a conniption.
Check the front wheel sensors for buildup. You can get the rust bits off with sticky tape.
As far as the brake light goes, try pushing up on the emergency brake pedal when it's doing the light.

[85square]

Thanks for all the replies guys!

My question now is, what exactly does the EBCM do and will it cause any issues if i dont fix it? (other than the fact that it won't pass inspection) Also is there any ways to tell that its definitely the EBCM?

[95 S_Trucker]

The EBCM is a electronic module that gets inputs from wheel speed sensors, and it will activate the ABS when needed. Its basically the brain for the abs system.


Why wouldn't it pass inspection? I did a search and it looks like warning lights can be on for the ABS system, but it will still pass.

PA is very similar. You can only fail if there is a hydraulic problem, not for an electrical problem.

[95 S_Trucker]

You will need to get the abs codes scanned before you proceed.

[izzy_Britton]

Originally Posted by 95 S_Trucker

The EBCM is a electronic module that gets inputs from wheel speed sensors, and it will activate the ABS when needed. Its basically the brain for the abs system.


Why wouldn't it pass inspection? I did a search and it looks like warning lights can be on for the ABS system, but it will still pass.

PA is very similar. You can only fail if there is a hydraulic problem, not for an electrical problem.

totally off topic here... but man i feel bad for you guys up in the north east. I thought california emissions testing was a ridiculous dog and pony show for no reason. if they test all your stuff up there, man i feel privileged (not really the smog tests are a PITA) but you get my drift.

I wonder if my TECH2 scanner can program the EBCM? i will have to look to see if it is an option. I just bought it and havent had much chance to play with all the features.

-Izzy

[95 S_Trucker]

A tech2 might be able program it. My snap on scanner will let me change the tire size, but not the axle ratio


I don't know about NY, but in PA, we have safety inspection in all counties, and emissions inspection in the more populated areas(about 1/3 of the counties).

The general consensus is safety inspection is ok, but emissions is a waste of time.