[dieseldoctor5992]

Sometimes when I stop at a stop sign or when I start my truck the brake light comes on. My brakes stop the truck but they seem alittle weak to me. if the light is off and I pump my brakes a couple times it comes on then goes off after it sits running for a second. are they losing vacuum or is there a bad valve somewhere. what does the brake dummy light indicate.

 

[madmikeismad]

Check your brake fluid? Maybe your powersteering? I don't know for sure, but being power assisted or whatever it's called, bad steering could effect the brakes I guess...

 

[RPegram]

The "dummy brake light" is controlled by a vacuum switch located on your driver's side inner fender up near firewall. What it is telling you is that you don't have sufficient vacuum for your brakes to operate properly. If you had a gas engine, then your sorry idling and runnig awful would let you know, but being a diesel and having a vacuum pump, Dodge thought they might need to add something else to give a little early warning before you take out the rear end of the car in front of you. First verify you don't have any vacuum leaks. Cut the truck off, wait a while and pull a vacuum hose and see if you hear a little "whoosh" of air. If no "whoosh" then you probably have a small leak somewhere and it is time to go hunting. If "whoosh" then you can check vacuum at pump and make sure it is within specs. It is also common for these trucks to lose sufficient vacuum for braking at idle with pumping of brakes at idle. This is reason Dodge went to hydraboost in '97 and got away from vacuum assist. It is also normal for brake light to come on when you first crank until sufficient vacuum is developed to turn off the light.

 

[Joe G.]

Also check your parking brake. Pull the spade connector off and see if the brake light is still not behaving properly. If the ABS light is on too then you have a different problem. Any failure in that system also turns on the brake warning light.

 

[12valveterror]

i had a mouse chew through the 2 wires that run back to my abs sensor on the rear axle and had the brake light and abs light come on, so could be something like that too haha

 

[madmikeismad]

I'd hope that mouse fried itself.

Sorry I posted about the hydraboost, I thought that started earlier than '97.

 

[12valveterror]

yea i thought it was late 96 but could have been 97 but anyways there is a small plug looking thing right below the master cylinder i think it has one wire to it and like an inch long whitish plug, that could be loose, im pretty sure i pulled that off and had my brake light come on i wish i had a pic to show you.

 

[revlis240]

go to the vac line coming out of the vac pump. you will see a T in the line, with a smaller line going UP to the ledge of the firewall. Break that line in half.

Blow (with your mouth) into the line that you cut and you will find your leak real quick. youll hear the leak hiss as you blow into the line. When you find the leak, mend the plastic line with a small piece of rubber vac hose and youre good to go.

on my truck, the brake/abs light JUST came back on, and i found/fixed the leak and the lite is still on. I think the little pressure switch fried itself, but the only way to know for sure is to get a vacuum guage and check to see if its actually getting the proper vacuum. contrary to the one of the posts above, taking the wiring plug OFF of the vacuum switch actually turns OFF my brake light...

 

[dieseldoctor5992]

I got a vacuum gauge and checked and on the t from the large hose from the vac to the brake booster I had 27inHG but any where else I could only get about 10 so I started pulling hoses and plugging them with my finger and found that some battery acid had got to my vacuum line to my cruise control. So I fixed my vacuum leak and got my cruise working. arty018: