ok so i've dropped the glove box and grounded the connector.... and i see this sequense short, short, short, short, short, short, long. and it does this over and over until i unplug the system. when i plug it back in both the abs and antilock light come right back on. the connector to the sensor on the axle was broken so i hard wired it, but lost which wire went where. the first time i tested there were 7short and 1 long, so i swapped the wire. then i got the 6 short one long. so i cut em both and left it unhooked, still the same. so i unplugged the whole RWAL thing on the rear axle and once agian came up with 6 short and one long....
6-Erratic speed sensor reading while rolling
7-Electronic control module fuse pellet open, isolation output missing, or valve wiring shorted to ground
8-Dump output missing or valve wiring shorted to ground

i'm not sure whether to count the long light so it's one of these there. i'm also not sure it's "reseting" i followed these instructions to reset
"I would unplug the module behind the glove box ( straight inside) before worrying about trouble shooting. Mine acted up one time and that was the fix...needed to be reset. Disconnect for 5 seconds."

i have another RWAL off a wrecked truck i am going to got plug in the wiring and see if anything different comes up.

 

You have a code 8, the long flash signals the beginning of the code. Kinda goes along with what we've been discussing in PM.

 

8-Dump output missing or valve wiring shorted to ground

ok can someone please expand on that.... I changed the RWAL but have yet to connect the sensor over the rear axle. could that be throwing the code? also the PV is still pushing the pin out. now on the road test it felt better and pedal wasn't low like it was before. brake pressure is still kinda high but that may be an unrelated low vacuum issue or something.... anymore ideas dave (or anyone else)?

 

the dump valve is on the frame rail next to the rear end, if you have a spair, i'd change it, but, the code sound electical,bad conector,conector pins,wiring pinched or cracked wires.

It sounds like like you'r going to need to start studding a wiring diagram soon!

 

already threw in the spare, can anyone tell me why it keeps poppoing the pin out on the proportioning valve? this is getting annoying!

 

Micaiahfied,
Can't comment on the RWAL codes, but the prop valve I know something about. In the biz it's known as a combination valve and the part that pops out is the delta-P switch (delta means difference in and P for presure). Inside it's a spring loaded floating piston that is centered between the primary (front) and secondary (rear) hydraulic circuits. As long as both circuits build equal pressure, the valve stays centered and the pin stays in. If one circuit has pressure and the other doesn't, like if a line breaks, the circuit with pressure pushes the piston out of center, causing the piston to push up the pin which creates an electrical ground and turns on the brake warning light. To shuttle the piston there has to be a pressure difference between the front and rear. Possible causes: Air trapped somewhere, a leak, the RWAL valve stuck and always dumping pressure, the rear brakes way, way out of adjustment, rotors really warped and pushing the caliper pistons way in. The delta-P will trigger if there is a momentary imbalance in the system and you hit the pedal hard enough (like if the rears are out of adjustment or the warped rotor thing) though it would be unusual and the condition would have to be extreme. I'd suspect the bleed first, and then the RWAL. Feel free to PM me if you think I can help.

Brian

OOH! OOH! Mr. Kotter... I have seen master cylinders fail such that fluid bypasses the piston on one circuit and returns to the resivior. This will trigger the delta-P, give a low or long pedal and since one half of the system has no pressure give poor performance. This can happen with no external indication. You could troubleshoot it by plumbing in a gauge at the M/C ports. Don't go at the wheels as this will include the prop-valve and confuse the issue. Use a trailer T, so that the rest of the system is included. If you just deadhead the M/C you may not get enough stroke to include the leak. If you do, brake system peak pressures are in the range of 2000-2500 psi, so you'll need gauges that can show that pressure.

 

You have been fighting is problem for a while and i thike that brian is you road to the ansore...just clue all the rest of us when is found!!

 

well here's my plan of action at this point... i am stick of this and the parts i have left to replace with new parts are the PV RWAL and axle sensor. at this point i think i am gonna bypass the rwal completely and install an "adjustable proportioning valve" so that when i am running empty i can lower the pressure to the rear wheels. since i am putting that in i am considering just running new hard lines... in the front running them straight to the soft line on the axle and on the back, throught the adj PV and then on to the soft line in the back. i am getting a new booster/master combo free cause something just isn't right with this thing. i was reading over on TDR and a guy there bypassed the RWAL and is loving it. here's the thing i am worried about, i'd like to leave the factory PV but will the adjustable in line after it cause that little pin to pop out when i don't want it too? the safety feature of that pin is nice, but the problems with is have been annoying as well.

 

The adjustable valve will not pop the pin out if it's after the factory valve.