Do I have RWAL, ABS, or none?

[sablazer]

Hello all,
I am new here and I am pretty sure I may have seen a thread about this but.... I have an issue. I keep seeing that my 91 k5 is "supposed" to have either ABS, or more commonly RWAL however, I do not have any wheel sensors or any other indication that I have any form of ABS and I am not sure if it was an option. I pulled the build sheet on it and there is no RPO for any ABS or RWAL. I have a black module next to the brake booster, but as far as I can tell, it only affects the brake light function and cruise control. I have the common "E brake light at 36 MPH" problem. Here is what I have done so far (as I had a rear end shake anyway):
1. Replaced rear drums, shoes, wheel cylinders and hardware.
2. Replace front rotors and pads.
3. Replaced brake switch.
4. Bled the utter crap out of the brakes.

I imagine the next step is to change the prop valve, but it looks damn near brand new from the p/o and is don't think that is the problem.
My questions are:
1. Does my k5 actually have any ABS?
2. Can a bad brake model cause this issue?
3. Is the loss of cruise control the result of the issue?
4. What is the next/cheapest step to find the problem?
I could just take the bulb out, but then I might as well remove the brake module and wire up the brake switch.

 

[tRustyK5]

You have RWAL.

I've never heard of the 36 mph brake light. Might be a bad ABS module, which is that black thing next to the master. Frankly I feel the RWAL is next to useless on a K5. On a long bed pick-up it may have had some value...

I have a 90 with the same RWAL and am replacing all my lines front to back anyways, so the RWAL is coming out.

 

[sablazer]

How does the RWAL operate without any wheel speed sensors?

 

[dremu]

1990-91 Blazers and Suburbans all had the RWAL, yep. Runs off the same thing that drives the electronic speedometer (DRAC, VSS, whatever you wanna call it.) Think it's on the output of the transfer case.

You can unplug the electrical connector at the module with no ill effect (well, you'll no longer have rear-wheel ABS, but it only works in 2Hi and when the planets are aligned anyway.)

-- A

 

[sablazer]

So the ABS module does not have any affect on the cruise control?