Brake light on when cold but off when warm

my dads 04 tacoma 4x4 is having a problem i cant seem to find with basic looking. The red brake light that turns on when the ebrake is pulled turns on and stays on when it is cold outside (50 below) and turns off if its warm out. I checked the pivit arm for the ebrake and its fine aswell as topped his fluid off. What are other things that could cause that??

 

Bump

 

I think the switch is under the dash on the handle asmbly.

 

What do you mean?

 

The switch that activates the light can get sticky. As well as the float in the brake reservoir that activates the light.

The actual brake being hung wont' activate the light, as the switch is in the engagement mechanism in the cab.

 

How do i access the switch?

 

It's a foot brake, right? Crawl under the dash and look. Or be smart and use a light and a mirror.

 

My 01 was doing this a few weeks ago. Topping off the fluid in the master made it stop. It's odd though because it really wasn't low, it was about half way between min and max. Apparently the sensor can be pretty touchy.

 

The 1st gens have a hand brake...

 

I think i found a switch but it is in a sealed box so no way to clean it. Not dirty at all tho. Never heard of a float in the master cylinder either. I topped the fluid off as it was alittle above the min line but not to full. Is there anything that could get "stuck" like a float?

 

Then it will be around the base of the hand brake. It can look clean but still be sticking; the plunger can get gummy.

 

Most sealed switches can still be cleaned/opened. You just have to be careful.

 

There is some form of sensor. Follow the wires.

 

Look under the pickup as well. There is a return spring under there. Sometimes they fall off. Or - like most of these old hand brakes it's all stretched out and could use a refresh. $130 for the rear OEM part and less for the dash piece (cable). Easy to replace as well.

 

If you unplug the switch on the hand brake, the light won't come on when you pull the hand brake. That can be one way to test and narrow things down

 

He is right here. but the switch has no adjustment. 9 times out of ten your rear brakes are out of adjustment!
When the light is on next time take 1 finger and push the brake lever in a tiny bit more and it should go off........if it does and comes back on when you let go then your rear brakes are out of adjustment. getting all the slop\slack out of the rear brakes tightens up the cables also. the wheel cylinder is the power\hydrolic side of the brake but if there is too much play in it. it will over work the front brakes and warp your rotors faster also.
If it has ABS then you can test the rear brakes on a wet road...stab the brake pedal and if you feel like your being thrown out of your seat and there really touchy then only the fronts are grabbing and rears are out of adjustment. I F'n hate drum brakes. I hated them in the 80's and i still hate em.

 

Thank you for all this info. Very helpful. Im going to run so tests and see what i can find. If it ends up needing rear brakes then off to the ahop it goes because i HATE drums aswell. A pain to work on.

 

I'll start by saying discs are easier.

But drums are not hard if you use a methodical approach and take your time. Expose the guts, clean it down well, take photos of assembly. Disassemble, finish cleaning, start reassembling new bits, using your photos as reference. If you get in trouble, pull the other side, look at it (remember it's a mirror) and use it to guide reassembly.

There's no reason to pay a shop 3x the cost of the parts to accomplish something pretty straightforward. Unless you have to sit in the snow to do the work. Then maybe.

 

It's all we used to have. All 4 corners. We wern't any better mechanics, just had to do what we had to do.

Shops have always advertised 'Brake Jobs----all 4' or later 'per axle' but they always have tied to find ways to jack up the price once in.
Last time I used a brake place (Sister's car, I didn't feel like screwing with it) they had it so screwed up I had to start over. And that was a guy who said he had been doing them for 30 years. *he put on a booster that was remanufactured wrong. Told me the ABS pump was messed up.
Point is: You can do them 3 times over (even if you buy a few tools) for what they charge to mess it up then tell you it's your problem now, get on down the road and your just as frustrated AT THEM as if you had tackled it yourself.

 

Just went through this and concluded the front seciton of the parking brake cable was very stretched. Haven't changed it yet but is looks stretched out.