Brake warning light comes on sometimes


AccordCodger
11-17-2005, 07:26 PM
ANOTHER intermittent problem (I hate that kind).

When the car has been parked all day (but NOT all night), and I drive off, after about 1/2 mile the brake warning light comes on. It stays on for about 20-30 seconds, then goes off and stays off (for my 50-minute, mixed highway/urban commute home).

I checked the brake fluid level and that's OK. Oh - and by the way - tapping the brakes doesn't affect it, nor does jiggling the parking brake. The brakes do, however, work normally which the light is on (though I admit I haven't attempted a crash stop at that point).

Suggestions?

WEF
11-21-2005, 05:09 PM
Are you absolutely positively sure the fluid is not low? Our Camry's reservoir looked like it had enough in it and there were no wet spots around the backing plates and the pads had only 20k miles. The caliper slide pins on both wheels were corroded, causing the pads to drag and prematurely wear almost to metal.

Fill it to the top and if that fixes it, check the pads.

AccordCodger
11-21-2005, 07:09 PM
Absolutely positive. Checked it on two occasions. Took the cap off just to be sure.

BTW, it SEEMS to stay on a little longer (and even come on again very occasionally during driving) when the weather is colder. Mind you, this is Florida, so we aren't talking MUCH colder :)

DFBonnett
11-22-2005, 09:42 AM
Is the connection clean where the harness plugs into the master cylinder? Just a WAG.

WEF
11-22-2005, 01:29 PM
Is the connection clean where the harness plugs into the master cylinder? Just a WAG.

I think the switches in the "fluid low" position go to ground. Leave the connector unplugged. If the problem goes away with it unplugged then it would be a faulty master cyl. switch. I guess the one for the hand brake is in the console.

Do you have ABS?

AccordCodger
11-22-2005, 06:30 PM
I'll check the switches (starting with the fluid reservoir - easiest to get at). And the one on the parking brake is less likely IMHO to cause this kind of behavior - I'm sure it's a more robust switch.

No - no ABS.

PS Much colder today - light stayed on a lot longer this morning (probably 5 minutes) and came one for about another minute or 2 half way though my commute.

AccordCodger
11-23-2005, 01:31 PM
Well, it looks like it's the fluid level switch. I unplugged it and --- no warning light now. I'm not sure what the deal's going to be with a replacement. Unlike the Honda, it isn't as simple as replacing the cap on the reservoir.

AccordCodger
11-25-2005, 09:08 AM
The switch is part of the reservoir, so it's a messy job to replace that. I'll just live with it for the time being. (Before all of you start giving me ominous advice about not being able to rely on the fluid level warning, I've been driving for 40 years, and for most of those years, my cars didn't HAVE a fluid level warning!)

AccordCodger
02-13-2006, 09:18 PM
Well, finally solved the problem accidentally. I changed the (front) brake pads, and didn't suck any fluid out of the master cyl. So now the fluid level is a little higher than it used to be, so maybe that's the reason the light doesn't come on any more.

lenjack
02-14-2006, 08:52 AM
I'll vote for low fluid level. On 2 Camry's, my brake light came on intermittently. I looked at the fluid levels and they looked good. After a week, I added fluid and the problem was solved. It is very difficult to properly eyeball the fluid levels.

RIP
02-14-2006, 05:41 PM
On both my 87 and 94 I've noticed the fluid level can be nowhere near the low mark and I would still get a light. Need to keep them filled up to the brim. Unfortunately, from time to time we all have to learn something the hard way, myself included. Thanks for letting us know what happened.

Add your comment to this topic!