My brake warning light illuminates after driving a few yards. I have bled the entire system several times. New master cylinder. Plenty of brake fluid, I'm thinking it must be the combination valve. With the truck turned off, if I check continuity between the sensor and a ground, I get no continuity. Not the parking brake switch. No fluid leaks. How does the sensor detect air in the lines or a fluid leak. I don't see a brake fluid level sensor.

 

Brake or ABS?

Check the parking brake SWITCH; it may be jiggling and grounding out the light.

For a test - AND ONLY FOR A TEST - unplug the combination valve and see if the light goes out.

How does it detect air in the lines? Read what a combination valve does! https://www.freeasestudyguides.com/c...lve-brake.html

RwP

 

Thanks Ralph. The red brake warning light goes out after starting but comes back on after I apply the brakes a couple times. Just to be sure, I disconnected the parking brake switch and I still got the light. I put in a different combination valve from PicknPull. The new valve looked good. Unfortunately I still get the brake warning light with the new valve. So, I unplugged the switch on the valve and still get the light.n what the hell? Now I’m thinking it is a problem in the wiring to the warning light, instrument cluster or somehow the ABS system is triggering the light. Does the ABS system have a separate, amber warning light? If, so, that light is not illuminated.

 

It may help to know what year and if you have RWAL or AWAL (Rear wheel anti-lock or all wheel anti-lock).

But yes, the brake light is also driven by the ABS controller for those years with either flavor of ABS.

If yours is a 1995 or 1996, the factory service manuals are in the FAQ; I'd download the appropriate one and start checking it. I'd also consider replacing ALL the lights in the cluster; it's old enough that they may be dying with age after all.

If yours is a 1991 to 1994, the 1995 manual MAY be helpful, or it might not; I've never compared to say for sure what's different from a 1991 with RWAL and a 1995 with AWAL

If it's not a 95 or 96, then I'd recommend obtaining the factory service manual - they're available used on Ebay, or new paper from Bishko Publishing (expensive!), or new on disc from Bishko and other sources (for instance, Summit lists them as a special order item; I think Jegs does also, but haven't checked recently.) BTW - Free hint: It's not a Chilton's Dakota or a Haynes Dakota; neither book is the FACTORY service manual, and due to the fact they cover several years in one book, they're about useless as a screen door on a submarine when it comes to wiring.

RwP

 

It’s a 1995, 5.2 L. All wheel ABS. I’ll start checking the ABS system.

 

Be sure to grab the FSM from the FAQ link then. It'll be very, VERY helpful.

RwP

 

I do have an original Dodge service manual. I started looking at the ABS system by checking the fuse and relays. Turns out the ABS warning light relay socket was empty. I put in a relay and now I have, and probably had all along, both the brake and ABS warning lights on. So, now I’m working through the ABS system.

 

I ordered a rear ABS sensor. I’ll put it in late tomorrow. Front sensors look Ok. I cleaned all the ABS electrical connectors under the hood.

 

So I started looking at the ABS system. The front sensors looked good. The most likely, and easiest to fix is the rear ABS valve block, with two solenoids that can stick closed, and the rear ABS speed sensor, bolted to the rear differential. I took off the valve block, took it apart. Cleaned all the parts with brake cleaner, put it back together and reinstalled it. No luck. Then I replaced the rear ABS speed sensor. That was the culprit. No lights now. Hurray.

 

Glad you fixed it!

I bet a previous owner unplugged that relay to kill the one light.

RwP