2nd Gen Non-Engine/Transmission brake light still on, need some more advice..

[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

 

[madmax4688]

when you said you replaced the switch which one was it? The one at the brake peday or the one at the ebrake?

 

[coadman]

I replaced the one at the brake pedal, as when I checked each terminal at differant positions for continuity, the terminals for the cruise circuit were faulty. When I replaced that switch, my cruise worked, but my brake light is still on. I just reached up and manually triggered the E-brake switch, and it made no differance, or is that a feasible way to check the E-brake switch?

coadman

 

[madmax4688]

I just reached up and manually triggered the E-brake switch, and it made no differance, or is that a feasible way to check the E-brake switch?

coadman

Ok I would try and unplugging the ebrake completely and see what happends. If the switch is bad it might be internal and you wont know until you unplug it. let me know.

 

[jtwcummins]

Here it is again, this is what turns on the brake litte. Most common failures are the sensorat the master cylinder and the e brake switch. If you have rear anti lock that circuit can do it to. On 4 wheel abs the abs lite will probably turn on w/ or without the brake lite. Disconnect the wire to the master cycliner/proportioning valve. Litte is turned on by applying ground.



Brake Warning Lamp

The brake warning lamp gives an indication when the parking brake is applied, when the pressures in the two halves of the split brake hydraulic system are unequal, or when certain problems are detected in the Rear Wheel Anti-Lock (RWAL) or Anti-Lock Brake Systems (ABS). The lamp is turned on when the ignition switch is turned to the Start position as a bulb test. After the bulb test, the lamp is controlled by hard-wired inputs from the parking brake switch, the brake warning switch, or the RWAL control module/Controller Anti-lock Brake (CAB).



The brake warning switch closes to ground when it senses unequal hydraulic pressures in the two halves of the split brake hydraulic system, possibly due to low brake fluid level or brake fluid leakage. The parking brake switch closes to ground when the parking brake is applied. The RWAL control module or CAB can also turn on the brake warning lamp if certain brake system faults are detected.

 

[coadman]

This is a 4x4. If I unplug the switch on the E-Brake, do I need to jumper the switch terminals or anything to see if light goes off of if EBrake switch is bad, or just simply unplug? Also, is there a way to check the sensor at the master cylinder? I do have a volt meter, so if there is a way, kindly point me in the right direction, and I will give it a try.

thanks,

coadman

 

[jtwcummins]

no, just disconnect them, they supply a ground to lite the lite

 

[madmax4688]

I dont know about the master cylinder but you can just unplug the ebrake wire from the switch-no jumper needed. That wire just goes to ground when the ebrake is pressed so if the switch is bad then unplugging it will turn off the light. Hope this helps.

 

[coadman]

I dont know about the master cylinder but you can just unplug the ebrake wire from the switch-no jumper needed. That wire just goes to ground when the ebrake is pressed so if the switch is bad then unplugging it will turn off the light. Hope this helps.

I unplugged the wire going to the E-brake switch, but light continued to stay on. So I plugged it back in(guess that eliminates the E-brake switch?) Let's take it in order(1) unplugged brake light switch, light stayed on, switch should be good?

(2) replaced "stop lamp switch" on brake pedal, as it showed no continuity on cruise circuit, brake light stayed on, but cruise now works Oo. (3) Checked fluid in brake cylinder, it is at full or safe level (4) All brake lights work, even the one in the middle of cab on rear. So with this all in mind, what else is there? I looked at the master cylinder, and saw a 4-5 wire harness plugged into it, and also a single wire plugged in elsewhere. I didnt see anything that looked like a "sensor"(which of these goes to the "master cycliner/proportioning valve. " that jtwcummins was referring to, either of them? This truck does have Rear Wheel Anti-Lock (RWAL) brakes.

Thanks,

coadman

 

[Fogie]

I'm not to sure on the 2nd gen, but I remember on the 1st gen that the RWAL sometimes needs to be reset. It was a matter of a momentary jump wire between two spuds on the RWAL Control Module. Sorry I cannot remember more. Check your manual for resetting the RWAL Control Module. I am glad to see that replacing the brake light switch cured your cruize control problem.



Terry

 

[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

 

[jtwcummins]

Pull the connections to the abs and the single wire to the Master. If it is still lit look for a short to ground in the wiring, the sensor is in the MS.

 

[coadman]

Pull the connections to the abs and the single wire to the Master. If it is still lit look for a short to ground in the wiring, the sensor is in the MS.

Ok, I can pull the single wire going to the Master Cylinder, no problem. Where is the abs connection?Is this the "Controller Antilock Brake" that my service manual is referring to? If so, it says it is located "Center of Instrument Panel". Can you shed some light on this?

thanks,

coadman

 

[jtwcummins]

This is fro RWAL



Rear Wheel Antilock Brake Control Module



The Rear Wheel Antilock (RWAL) electronic control module is located under the central portion of the instrument panel. It is mounted on a bracket attached to the back side of the panel. The module is accessible through an opening created by removal of the knee bolster.







Copyright © 2005 ALLDATA LLC

Terms of Use

 

[coadman]

Pull the connections to the abs and the single wire to the Master. If it is still lit look for a short to ground in the wiring, the sensor is in the MS.

Ok, Did as you said, removed single wire from Master Cylinder, and the multi-wire plug into the ABS controller. Brake light was out, when I turned key on and started truck. Now what, are we getting any closer to a remedy?

coadman

 

[jtwcummins]

plug in connections 1 at a time and see whats what. Most likely the master cylinder wirewill turn on the lite when connected.

 

[JRichard]

Sorry for the mis-diagnosis coadman, i really thought the switch would fix it, at least i got your cruise control fixed (small consolation) LOL



Jake

 

[jtwcummins]

The thing to remember is the brake lite is turned on by the parking brake, fluid level in master cyclinder, and pressure sensor in proportioning valve or master cylinder. Dodge uses 2 of these, but the brake lite won't stop cruise from working so you had 2 problems. Our trucks have vacuum lines for cruise under the drivers side batt and these get destroyed by acid etc from the batt making cruise not functional. Other common failure is the brake pedal switch which was your problem or the switch on the clutch for a manual trans.



The electronics dosen't fail very often so the mechanical, switches, relays, etc, is the first place to look. Right after getting a degree in automotive engine performance I worked in a local shop and was surprized to see them idle a car for hours when it had an intermittent problem waiting for it to fail. My process is to remove and clean all the electical connectors use cleaner and dielectric grease loosen and retighten all grounds, this fixed most issues.

You might be able to fix the issue you have by doing a power flush of the brakes removing crude from the system, if not a new master cylinder might be needed.

 

[Joe G.]

I was hoping you folks could come up with a solution to this problem. I have cleaned all connections associated with the RWAL. I have changed the sensor on the diff. The parking brake switch works fine. There is no trouble with the master cylinder associated stuff. The RWAL sets the ABS light on during the test phase and it won't turn off. Sometimes if I get it in gear and rolling I can prevent the test phase failure, but it will turn the ABS light on the next time the truck is stopped. The wiring diagram in my '95 service manual shows a connection to the brake light driver from the RWAL. I have not figured out what to do to turn off the RWAL fault yet. If I could disable the RWAL to prevent the ABS light I would do so. I don't want to completely disable the brake light because I want it to light if there is a master cylinder or parking brake problem. There was a guy on here a couple of years ago who explained how to cause a fault but he did not know how to stop the fault that is causing the ABS light to turn on. The ABS light disables RWAL so I really don't have that anyway. I suppose that I could put a piece of black tape over the red brake warning light, but I would like that to work. Any ideas?

 

[jtwcummins]

If you are talking abs lite and not the red brake lite it is a whole different animal