coadman

On my '97 3500 I just purchased about 2 weeks ago, my brake light on the dash was lit, and also my cruise control didnt work. After receiving numerous replies from helpful people on this site, I figured the stop light switch on the brake pedal was faulty, so I replaced it. My cruise control works now,, but my brake light stays on. My brake fluid resevoir is at the full level. Park Brake works and holds well, and seems to disengage fully when lever is pulled for release. What else do I need to check?(My son says to just put some tape over the light, problem solved )
coadman

Mopar1973man

The brake trouble light is on for a reason. There is still a problem with the brake system somewhere. Make sure you E brake pedal is returning fully. I've seen some trucks with slack in the cable and the pedal will sag a bit causing the light to come on. This can be fix by tighten the slack adjustment under the truck.

If the problem isn't the parking brake then it is a brake fluid problem. There are only two thing that trip the light E-Brake pedal applied and brake system failure (air in system).

There is one more thing that trips the light but it has a extra light. ABS and BRAKE will light if there is a ABS problem.

infidel

Some codes, especally brake problem ones, will keep the light lit for 60 engine on/off cycles after the problem is corrected unless cleared with a code reader.

coadman

I had the Dodge tech check for codes when I went to pick up the brake light switch. He told me there were none. I returned home with brake light still on, and installed the switch. After that, the cruise control worked(as I suspected, as those two terminals failed the continuity test I performed earlier), but the brake light on dash is still on. I had previously reached up and manually pressed the E-brake switch to see if that would make it go off, it didnt, or is that the correct procedure to test the E-brake switch. Other than the E-brake switch, I dont really know where else to look, as, like I said the brake fluid level is fine. I have a service manual setting on my desk, all I need is some more "prods" in the right direction, so I can do some more troubleshooting.
thanks,
coadman

Mopar1973man

There is also a sensor out by the master cylinder that tracks the pressure to front and rear of the system. If there is air in the system the balance of pressure will be off and it will cause the light to pop on.

The brake fluid can be full at the same time there is air in the system. I would try bleeding the brakes to be sure... Also brake fluid will break down over time. It seems to suck in moisture. There is no listing of it but you should change your brake fluid whenever DARK or every 30K.

Speaking of this mine is coming due soon... (starting to darken and 57K on the clock!)

coadman

I was doing some more reading in my truck manual, and also my service manual. I have the RWAL brakes. Does this mean that the "ABS" light on my dash, should go on, briefly, with every start-up or when the key is turned on? If so, the "ABS" light never goes on. I had to look in my manual to see where it was supposed to be located. Does this shed any light on the subject for anybody?
thanks,
coadman

Mopar1973man

Yes, The ABS light does come on for a bit at startup to test the bulb. More than likely the bulb is burnt out.

If so that most likely means the the ABS light is on too. (Might not but)... So the speed sensor in the rear end died.

coadman

I havent bled the brake system(yet), I was looking for other possibilities before I do that chore. Are you saying a speed sensor could be bad, which in turn keeps the brake light on?
coadman

coadman

A person on another Cummins Truck forum told me to unplug the single wire going to the master cylinder and also the multi-wire plug at the ABS controller under the dash. I did this, and the brake light was out when I turned key on and started truck. When I plugged the wires back in, the brake light came back on. Does this information provide any clues as to what my next step should be?
thanks,
coadman

Korney

At least you can drive around with no daytime running lights cause they shut off with the e-Brake. Just hit the park lights and look cool eh.

Rob

Check up against the firewall, look for a small white plastic switch with a copper bar laced through it. The single mounting screw could be loose, the copper bar can fracture or it could simply be corroded and need to be cleaned up. There is a single wire going to the switch. If you unplug it, it will open the circuit and the light will go out. You can diagnose the issue by pulling the wire off the spade connection of the switch. If the switch is faulty and everything else is intact, the light will go out.
Good Luck!
Rob

jrs_dodge_diesel

One thing you can do to test whether the ABS bulb on the dash is burnt out is to perform the instrument cluster test.

Insert the key into the ignition and rotate it one click forward to the OFF position. Push and hold the odometer reset button and then turn the key one click forward to the ON position while continuing to hold the reset button in. This will start the test:

- The odometer will read CHEC (you can let go of the odometer reset button here). The Wait To Start, Air Bag, and ABS lights should also light during this step. The PCM controls the instrument cluster, but the ECM, airbag module, and ABS module will function like normal during this which is why their lights are lit at first.

- The odometer will then change and read all 8's. The CRUISE and TRIP indicators under the digits will also be lit. No other indications will be lit during this part of the test. This lasts for about 5 seconds.

- The odometer will then test each and every segment of its display in sequence

- After that, every indicator on the dash will light up, with the exception of the Wait to Start light, turn signals, and high beam indicator. The WTS light is under control of the ECM which is why it does not light during this part of the test.

- The indicators will go out and then all of the gauge needles will move together in three steps. ¼ scale, ½ scale, and then full scale. The exception here is the fuel gauge, it will read 1/8, then ¼, then full.

- The gauges will go back to zero and the test is over. The door chime will sound and the instrument panel will return to normal.

That is a sure fire way to know if the light is burnt out. Also, here is a piece of the service manual describing the ABS module:

Hope this helps.