ABS light on 1990 Club Wagon E150

As the subject line says, the ABS light is set on my 1990 Club Wagon E150 w/ towing package and E4OD. I replaced both the VSS at the transmission, and
the VSS on the differential, but no change. The light goes off only briefly upon startup, and then comes right back on and stays on all the time, like its a hard fault of some kind.
Is there a way to check ABS codes on this model? I have an Actron EEC-IV code scanner, but the book doesn't mention ABS at all.
Does anyone have an idea about what would set this code? Frankly I'm not even sure what the RABS system on this van includes.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 16 May 2005 23:51:47 +0000, CJB rearranged some electrons to form:

There is a procedure to get the codes out, it involves grounding a wire on the ABS module. However, I can't remember which one. Someone will here will have that. I would check your brake fluid level also. But before replacing parts you should see what the ABS module is telling you by checking the codes.
--
David M (dmacchiarolo)
http://home.triad.rr.com/redsled
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Anyone who can furnish this information or who has more advice?
Thanks
CJB
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wed, 18 May 2005 15:54:17 +0000, CJB rearranged some electrons to form:

Here's what Chilton's says about a 1997-2000 RABS module. Yours may be different. You'll first have to locate the RABS control module, but I have no idea where it would be in your vehicle.
"Locate the black RABS diagnostic connector. One half of the connector has a black/orange wire. Disconnect the connector halves, and attach a jumper to the black/orange wire. Turn the ignition switch to the RUN position. Ground the black/orange wire, and the ABS light should begin to flash. The code consists of a series of short flashes, followed by a long flash. Count the total number of flashes, this is the RABS trouble code. The codes will be repeated until the ignition switch is turned off. A code of 16 (15 short flashes and a long flash) indicates no trouble found."
By the way, have you checked your brake fluid level yet?
--
David M (dmacchiarolo)
http://home.triad.rr.com/redsled
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wed, 18 May 2005 15:54:17 GMT, "CJB"

Look under the dash to the left of brake pedal for the rabs connector (where orange/black wire connect to black wire). You can access the orange/balck wire there to ground it and get the code readout.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thanks to those who have responded. I've been out of town for a few days and just got the replies. I'll check this the first of the week.
CJB

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Ok, here's a problem. The orange/black wire that comes out of the RABS box wasn't connected to anything...
My van has the factory towing package, but I see no evidence of a brake controller ever having been installed. There is a 3 wire harness under the dash that works with the towing package. One wire is red/black stripe and is the hot to the BOO switch. One is black w/ green stripe. I think the faded label says "Feed From Bat." The third is Blue w/ Black stripe and has no label, probably it's come off.
The wires (except the red/black stripe) have been taped off. So here's what I did ;-) Figuring I have nothing to lose, I connected the black/green stripe on the harness to the black/orange stripe that goes to the RABS box. Guess what? The antilock light goes off. I tried to test it by locking up the brakes on dry pavement, but I didn't get enough braking action in the rear to lock them up either way, so there's no way to know if I fixed anything.
The only repair manual I have is a (useless) Haynes, and the wiring diagrams they have don't show anything past 1978. Anyone have an idea what I'm doing? lol
Is the black/green wire supposed to plug into the black/orange wire on the RABS box? What is the blue/black wire for, a brake controller perhaps?
Thanks for your help,
CJB

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Finally was able to get this fixed. Thanks for all who helped.
CJB

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 09 Jun 2005 17:15:28 +0000, CJB rearranged some electrons to form:

What was wrong with it?
--
David M (dmacchiarolo)
http://home.triad.rr.com/redsled
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
lol, you really wanna know?
There's a master cylinder switch that senses the fluid level. It was impossible to see the damage because it was hidden inside the connector, but it turns out that two of the three wires were corroded sufficiently that they broke off as soon as I tried to remove the plug. I had to "manufacture" a new connector because the old one was so corroded, but as soon as I plugged the wires in, the light went away.
I really never suspected brake fluid level, because I thought it would set the BRAKE light, not the ABS light. Oddly, that's not how it works.
It may also have had another problem, because I had already replaced both VSS's. The in-axle VSS was in bad shape, and the tranny VSS had exhibited an intermittent problem.
Lastly, I was never able to get the ABS computer to send me a code, which made it even more frustrating.
Again, thanks to all who helped.
CJB

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.