Why is my brake light on?

I noticed this before I got my ole 95.5 back from my neighbors estate. Brake light was on and I found the master cylinder fluid switch was the reason it was on. If I disconnected it, the light went out.

Now that I did a bunch of work to the truck, I replaced the master cylinder (with new front and rear brakes, calipers and wheel cylinders). I have the same issue. I find the fluid level indicator switch open with no fluid and closed when fluid is adequate. I am thinking this is correct and there is something wrong with the truck to cause this to happen.

Has anyone had this issue, and/or have suggestions on how to fix it? I can leave the fluid level connector off, but I wouldn't know when or if I ever have a leak until when it may be too late.


Thanks in advance for any and all inputs,
Mike

 

Check your ebrake stopper/cushion. Might not be related to your issue btw

 

Thanks 02, the E-brake switch works all as advertised, I believe at least. When truck ignition is on, if e-brake is disengaged... brake light is off. If I pull the E-brake handle out... brake light is on.

 

Mine did this just had to top off the brake fluid. Even though it was working the min/max line it just had to be closer to the max for whatever reason

 

always start there...

 

I put a new master cylinder in because I thought the switch was bad. It was not and works exactly like the new switch.

The fluid is full. If I were to let it drop enough in level, the light would go out. Not from being full.

Which now makes sense, if you unplug the connector… the circuit is now open. And would then get a brake light in normal circumstances. I don’t get a brake light with the connector unplugged. Someone with an early gen 1 can confirm this for me if possible.

Current situation for me is unplugged (open circuit for brake fluid) and the light is off.

 

My 2002 Tacoma has the same issue but only during the Winter months at under 50deg ambient air temp . After a few miles of driving the light will go off and was told it is the brake light switch ?????

 

Hmmmm. Thanks for sharing your situation. Thats odd to be temperature related. Here is SE Georgia, summer is here and it acts the same as it did when cold here also. Darn, lol.

I’m thinking something must be wrong with the truck electronics to expect an open circuit. Although the emergency brake all works like normal.

 

I'm a little confused, if this is the case when does the light stay on when it's not supposed to?

I would revisit the under-dash switch, it drove me nuts for a few months. Turned out the front cable was stretched just enough so the lever didn't fully depress the switch under the dash. In the interim I put a small piece of fuel tube over the brake lever.

 

It comes on with e-brake out even an inch. Goes off when released back in. Stays off.

Comes on if connector is on the fluid reservoir with proper fluid level. If disconnected, light goes out.


Thanks