brake and abs lights up when braking

[tobaccogrower]

when i hold my brake pedal down for longer then 5 seconds my abs and brake light comes on on my dash. checked brake fluid and it's full. brakes seem ok. whats going on? my gut is telling my probally the brake booster is on it's way out. have a happy holiday everyone!

 

[B.G. Smith]

Does it do this with truck sitting still? If so, it's probably the master cylinder leaking internally. I don't think the booster will turn on the lights. bg

 

[PToombs]

I bet the booster is bad. The vacuum leak will trip the low vacuum switch and make the lights come on. Put a vacuum guage in and watch and see what happens when you step on the brake pedal.

The vacuum pump might be getting bad, but I don't think so.

 

[tobaccogrower]

if i start the truck with my foot on the break pedal the lights will come on and stay on till i take my foot off the pedal. the lights wont come on unless i really step on the pedal hard. light footing it wont trip the lights. will a repair shop have a vacume guage? my buddys brother runs one. i'm just getting nervous with these lights coming on every stop light i come to! the brakes are alot diffrent then my 2006. i keep thinking i'm goinging to try to stop and just keep going and should have seen it coming with these lights coming on at every stop i make!

 

[cerberusiam]

Either a bad booster or more likely a crack in the lines/Fittings. There a couple of fittings and lines that are known for rotting and cracking issues. Before you replace the big parts start replacing the little things.

 

[tobaccogrower]

i'm not loseing any fluid at all. i'm going to have a buddy hook up a vacume guage and see what happens!