brake system warning light Flashing Brake System Warning Light & Chime when moving

[tjg79]

On my 2001 GMC Yukon XL 2500 6.0L 4wd I'm getting a flashing brake system warning light and the chime activates when the vehicle is moving.  Also, the Automatic Headlamp System appears to be disabled.

 

I suspect a faulty parking brake light switch. I was having an issue with the parking brake warning light not going out after releasing the parking brake about six weeks ago. The solution then was to reapply the parking brake and then release one or two times.

 

That solution is not working now, and the Automatic Headlamp System, which has a connection to the parking brake, is not working or disabled. To turn on the headlamps, I've got to use the manual switch.

 

The problem must be in the parking brake light system. I'm not certain if it's just a switch or a relay and/or fuse somewhere.

 

The brake fluid level is midway between the max and min level marks. The ABS warning light is not an issue here.

 

Does anyone have experience with this problem, and know the solution or troubleshooting procedure to fix this problem?

 

Regards

Edited September 29, 2019 by tjg79

[carkhz316]

It sounds like you have your problem narrowed down to the parking brake switch.

[tjg79]

Yes, it appears to be a faulty parking brake switch. It's a one wire switch. I disconnected the wire, and all the problems went away.

 

The vehicle systems thought the parking brake wasn't released, hence the chime when moving.

 

The parking brake electrical system is connected to the Automatic Headlamp System.

 

The switch is an easily replaced part, and only costs a few dollars.