PatrickGSR94

iTrader: (1)

I just noticed this afternoon that my brake dash indicator light is staying on dimly while driving. It's exactly like in this video (not my video), where it's bright when the e-brake is pulled, but when released and driving it's dim and sort of fluctuates:


I checked the brake fluid level, it's good. Float moves freely. I took the cap off with the engine running. With the float all the way down the indicator light is bright just like when the e-brake is up. But when the float is pushed all the way up fully, the light is still on dim.

I know the brake indicator light is connected to the integrated control unit and to the ABS control unit, but I can't figure out what else could be causing this light to stay on dimly.

Earlier this afternoon I did scrape my front right tow hook pretty hard on pavement while coming out of a driveway. Never noticed the light before that, but I noticed it when pulling up in my driveway about 5-10 minutes after that scrape. But I don't see how scraping anything under the car near the front right tow hook could cause the brake indicator light to stay on dimly.

Any ideas?

PatrickGSR94

iTrader: (1)

Also noticed that the brake indicator light is on dimly even with the ignition just in the ON (II) position, but the engine not running.

1998GsRIntegra

Is the e-brake releasing completely? Had a similar issue, but mine would just stay brightly lit for a mile or two then it would go out. Finally got around to addressing the issue a couple months back. E-brake cables were stretched, more so on one side than the other and where the cables connect to the rear caliper was really rusted. The pin that holds it to the rear caliper I mean. It wasn't allowing the cable to pivot on the pin because of rust. Took care of all that and no issues any more.

Your issue may be something entirely different, but I figured I'd share any way. Good luck.

PatrickGSR94

iTrader: (1)

Yeah I'll try to take a look at it. Also have to replace a busted CV axle I just found.

el crapitan

is there a screen in the master cylinder reservoir on this car?

PatrickGSR94

iTrader: (1)

Yes the MC reservoir has a filter, which I removed and cleaned out last night. No change at all, still did it all day today.

Here is an actual video of my car showing what it's doing. The e-brake and brake fluid level sensors are simple on/off switches, sending either 0 volts or 12 volts to the light. For some reasons something is causing this light to get a weak voltage signal.


Today I did try spraying PB Blaster onto the springs and levers for the e-brake on each rear caliper. Still no change, but I didn't expect that to do anything anyway, since as I said the e-brake switch is on/off only. It's not capable of sending anything less than 12V to that light.

el crapitan

try keeping the screen out completely. there was a tsb for this on my crv. took it out, and problem solved. it may be the same for your car.
the screen really isn't necessary anyways

PatrickGSR94

iTrader: (1)

Nope, already tried that when I had it out cleaning it. No change.

As I said the sensor on the reservoir cap is on/off only. There is no in-between that changes the amount of voltage going to the light like the fuel level indicator and sensor does.

el crapitan

tried discnnecting the ebrake switch?
is there anything else at all that you've noticed is not working when the iight illuminates?

PatrickGSR94

iTrader: (1)

Nope, everything else seems to be fine.

Was driving home tonight on the interstate and the light was fluctuating a LOT going from about half bright, getting dimmer, and even going out completely. But then it came back on dim a couple minutes later. I think there must be some wire with lower voltage touching a wire that goes to this light. It's the only possible explanation I can think of. Now I just need to get behind the cluster and around the ABS unit to inspect wires, maybe jiggle them around or something. I'll check the e-brake switch also.

el crapitan

without seeing a diagram it'll be shooting in the dark. lemme dig up the diagram and see what we can find

PatrickGSR94

iTrader: (1)

Have already looked at my Helm's. The only wires serving that light are the e-brake switch, brake fluid level switch, and it has connections to the ICU and ABS unit. But I'm thinking it could be another wire to something else that is adjacent to one of these wires that is causing it to get voltage, like maybe the wire insulation has worn away or something.

el crapitan

a short to voltage is possible.
a way to find it is to start removing fuses one by one until the light goes out. that'll find the circuit allowing the voltage source. if that is the problem

PatrickGSR94

iTrader: (1)

mmm good idea! I'll start with the fuses in the box near the ABS unit, as I'm hoping the issue is there and not buried up under the dash near the ICU.

el crapitan

once you find the circuit that it's shorting to, you can look that one up and see where they intersect...granted, that does turn out to be the problem

fcm

The "trigger" for the brake warning light is a ground, the E brake and low brake fluid level both supply a ground to the warning light, the light is supplied power as soon as ign. is turned on, so a short to power on the ground circuit would blow a fuse a short to power on the power side of light would do nothing unless it was a 12V+ constant power, then the light would be on all the time.

Something is suppling the warning light a ground.

With the ICU involved, my guess is it is a problem with the ICU.

You said everything else works, does that mean, interm. wipers, rear window defog, all your warning chimes, [key still in the ign., lights still on, seat belt warning chimes]?

Probems with the ICU are so common on older Honda/Acura it would not surprize me one bit if it was the problem.

One question, does the light get brighter if you pull the hand brake? 94

el crapitan

ahhh yes. ground switched. a short to voltage would do nothing, without a supplied ground. my bad. could try disconnecting in the circuit until it goes out, to narrow down the location.
if the icu is suspect, could try disconnecting it.
i'll let the vet take over from here though

PatrickGSR94

iTrader: (1)

Yes the light does get brighter when I pull the e brake, see my video above.

But how can a ground cause the light to come on dimly? I don't think you can have half a ground connection. I thought the only way to vary the brightness of an incandescent bulb would be to vary the voltage going to it.

el crapitan

you got it.
think of the effects of a poor ground in a circuit. the added resistance requires voltage to overcome it. this lowers the available voltage to the bulb, and in this case, for example, dims the light. the added resistance of the poor ground becomes a load and the circuit becomes a series circuit with 2 loads that must be shared.
with the e brake pulled, you allow a clear path to ground. because electrons flow to the path of least resistance, they flow through the e brake switch, and thus, light the bulb bright.
they don't actually ONLY take the path of least resistance. they are actually shared between the 2 grounds. but MOST will flow through the e brake switch.

all you need to remember is this simple, beautiful formula from ohms law: it takes 1 volt of emf to push 1 amp of current through 1 ohm of resistance. that is law. unchanging, and absolute. E=I/R.
E being voltage I being current and R being resistance.
sorry for the tangeant. probably lotta stuff you didn't need to know. but cool **** nonetheless

fcm

What el crapitan said.

It works exactly like how the Dash Lights Brightness Controller dims your dash lights, ground through resistance, as you turn the DLBC you add resistance to the ground for the dash lights.

I have seen this, [dim warning lights on all the time] due to pinched wiring or screws through wiring giving the wire a "slight" ground.

Because the ICU is part of the circuit and it containing a number of resistors/caps/diodes and so on an malfunction in it can easily supply that "slight" ground to the brake warning light.

As mentioned, it's easy enough to check, unplug the ICU, even if it is not the problem, it would eliminate it as the problem.94

PatrickGSR94

iTrader: (1)

Okay I think I'm on to something now.

In addition to the Brake indicator light, I've also been having trouble with the ABS light coming on at seemingly random times. Sometimes it seemed like it was coming on right when I started the car, approximately every other time I started the car. However now it seems to come on about 2 minutes after I start driving the car. The ABS light NEVER stores any codes. When I jump the service connector, both the Check Engine and ABS lights stay on steady, no flashing at all.

So I was poking around, trying to figure out the Brake light, pulling various fuses under the dash, disconnecting the e-brake and brake fluid level switches, I decided to run through the diagnostic procedure for when the ABS light is on but doesn't register a code. I got down to the ABS Unit connector where it mentioned a possible short to body ground that could make the ABS light come on.

I checked the diagrams and the wires coming from the Brake light and the ABS light are immediately adjacent to one another on the 26-pin ABS Unit connector, which is inside the right side quarter panel near the right rear speaker.

I'm starting to think the ABS light and Brake light issue are related and possibly have to do with this 26-pin connector. Maybe those two wires are shorted to each other or something?

fcm

That is definatly a possibility, unplug the 26pin connector and spray it down with contact cleaner, [WD40 and other sprays like it will also work] to see if it is just a connection problem.

Did you try unplugging the ICU yet? 94

el crapitan

thought about this a bit and, correct me if i'm wrong, but by just unplugging the unit, the light will go out indefinitely, since we're removing the power source as well. would need to go through the circuit, and at each connector, test the ground pin until you find the connector that loses the ground. that way it's isolated between the last connector and that one. or the unit that the connector was removed from. does that make sense?

fcm

Power for the warning light is supplied by the same fuse as the instruments, fuse 15 -10A.

Unplugging the ICU will not effect power to the light, only a ground.

With that said, you may be able to see any damage to the ICU by just opening it up, just like you can see the blown cap, when the intermitant wipers a rear window defog does not work.

Should look clean on both sides like this one...


As you can see, there are pins going in two directions, some of the plugs are in the fuse box, the ICU plugs into the fuse box, probably be easier to just plug in a new or known working one, maybe PatrickGSR94 can borrow a friends.

I have a few known working ones for diff. Honda/Acura at our shop so if a car comes in with a problem, I can just plug one of mine in, makes troubleshooting so much easier.

I also pick up ICUs and PGM-FI Main Relays anytime I find them at PicknPull, check/repair them for resale as used units, easy way to make a few $$$. 94

kodylive

could be the switch on the e-brake itself its like the one under the brake pedal when they go out your brake lights always stay on.