Parking brake light on

turtle4692 · January 7, 2016

This is my first post. I have a 2008 Chevy 3500hd SRW diesel with 97,000 miles. The problem is the parking brake light is on all of the time. I have replaced the sensor in the reservoir, fluid level is full, no leaks any where. I have also removed the rear rotors and checked the shoes and just replaced the brake switch on the pedal. The cables operate as they should and the parking brake works fine. Also with the parking brake light on the cruise control does not function. I have read in forums about the parking brake light on along with the ABS light but I only have the parking brake light on. The only other thing that I have read about is the float in the reservoir getting stuck. Can the float sink? I did check the light with the sensor removed (but plugged in) from the reservoir but the light is still on. Any help would be greatly appreciated. Mike

davester · January 7, 2016

First, make sure your parking brake is completely released. Pull the parking brake release handle, and then pull up on the parking brake lever itself.

If that doesn't work, check the connector/switch on your parking brake.

Formulabruce · January 7, 2016

First, make sure your parking brake is completely released. Pull the parking brake release handle, and then pull up on the parking brake lever itself.

If that doesn't work, check the connector/switch on your parking brake.

/\ THIS is your problem ! Switch on the release assembly is Not being opened due to poor release lever return function ! .

turtle4692 · January 8, 2016

Thanks for the replies. I have checked the pedal and it is returning to the top. As I said in the original post I replaced the switch. Any more ideas?

davester · January 8, 2016

I would suggest taking out the parking brake switch but leaving it connected to the harness, and manually operate it and see what happens, if the light goes out. If the light stays on, maybe also check with a voltmeter if it's working [that it makes or breaks the connection when the switch is activated].

You should be able to make the parking brake light go out by manually operating it. If not, something else in the harness or computer is going wrong, and you'll need a full-service manual and/or something like autogenuity [a much better scanner than a plain OBDII scanner at your local parts store] to scan for what the problem is.

If the light does go out when you manually operate the switch, then reinstall it and figure out why it's not operating right when it's installed. maybe there is some kind of adjustment mechanism?

turtle4692 · January 8, 2016

There is a single wire going to the switch so it needs to be attached to operate. I have tested it with a meter and it opens and closes properly.

davester · January 8, 2016

So then the switch needs to be connected to ground. If you ground the switch with a test lead, can you make the light go off?

turtle4692 · January 9, 2016

I have done that also. Makes no difference. I am pretty much lost as to what to check next. I've checked or replaced everything I can think of except for the brake fluid reservoir.

davester · January 9, 2016

It is VERY unlikely to be the brake fluid reservoir sensor. That is going to put up a "low brake fluid" or some kind of service brake system message on your dash, not turn on the parking brake light. And I don't think there is a float to stick in the reservoir, because I just replaced my master cylinder, and the old reservoir didn't have anything banging around inside when I was cleaning it [before I decided to just junk it because I couldn't get a seal kit for the master cylinder].

From cheapest/most annoying/time consuming to most expensive/likely fastest

1. trace the parking brake connector wire back to whatever computer it connects to. test the wire for continuity and test connecting the pin itself to ground [if you can do it with the connector attached to the computer].

2. get a full-service manual for your specific truck and run through it's procedure for figuring this out. Also, it will have the wiring diagram indicating where the connector goes to, making doing (1) a lot easier, and you can also trace the other side of the system, between the computer and the display to see if there is a problem on that side.

3. get something like autogenuity with the gm-specific enhancement package, which can go through all the computers and tell you what's up. it will tell you what the computer is seeing from the switch, so you can tell which side of the computer has the problem [switch to computer or computer to dash]. I would bet at least part of the debugging procedure that will be in the full-service manual will include using a tech-2 scanner [more advanced than autogenuity] to check out the computer, and in this instance, you probably can do the same kind of thing with autogenuity.

4. take it to a dealer to figure out.