hey lazy, i aint got nuff sense to find a wire. lol i just replaced the sensor on the pumpkin. no luck, it still burns, im gonna try the valve on the side of frame on drivers side next. should i have to have someone pump the brakes like when im bleeding the wheels? also do i have to re-bleed all wheels too? as for being dumb, forest gump aint got nuffin on me. lol ty.
bill

 

hey numberdummy, i dont feel at all that you have misled me. i thank you for any suggestions or ideas. all are welcome. the only way to find out anything is to try it. im gonna fix it one way or another, [i hope. lol] im gonna try to bleed the line on the frame as soon as someone tells me how. im not kidding you. a mechanic i aint, but i dont mind trying, again ty kindly
bill

 

OK you have eliminated the diff. sensor, at a cost. When bleeding the RABS valve body, open the bleed screw and have someone press the pedal down, then close the screw while pedal is held down. Release pedal when screw is closed. Repeat until no air comes out. If you get a good pedal after that there is no need to bleed the rear brakes. If that does not put the light out then pull the codes. One or both of the valves in the RABS valve body may be faulty. However make sure that both the rear brake lights work as a faulty brake switch will cause a fault code or even one deffective bulb.

 

Just an FYI, 87 was the first year Ford installed RABS on the full size trucks. The speed sensor on the rear end is only used for the RABS system on 87-91 trucks. The black wire to ground for codes is taped into the main wire bundle where it passes through the firewall near the parking brake pedal.

 

ok, i bled the rabs valve, light is still on, if i cant find the black wire with orange stripe, then i guess i'll replace the rabs valve. im 75 years of age and on a very small limited income. its hard to buy lots of parts, but im trying. it's also hard for me to get in these positions to check things such as all the bending and twisting. lol, but then again i am trying.
again, thanks guys
bill

 

Diag. wire Black/Orange located clipped to the main instrument panel wiring harness about six inches from the firewall near the parking brake pedal.

To pull ABS codes the ABS light must be on also note if the Brake light is also on. When the ignition is turned off, ABS codes are cleared.

Turn ignition on momentarily ground the diag. wire.

Codes consists of a number of short flashes and ends with a long flash. Count the short flashes and include the following long flash in the count to obtain the code number. For example, three short flashes followed by one long flash indicates Flashout Code Four. The code will continue to repeat itself until the key is turned off. It is recommended that the code be verified by reading it several times.

Code 1 This code should not occur
Code 2 Open Isolate Circuit
Code 3 Open Dump Circuit
Code 4 RABS Valve Switch Closed
Code 5 System Dumps to many times
Code 6 Sensor signal rapidly cuts in and out. Condition only occurs while driving.
Code 7 No Isolate Valve self test
Code 8 No dump Valve self test
Code 9 High Sensor resistance
Code 10 Low sensor resistance
Code 11 Stop lamp switch circuit defective
Code 12 This code should not occur
Code 13 Speed Processor check
Code 14 Program check
Code 15 Memory failure
Code 16 This code should not occur

 

I have (had) an '87 will the rabs (and yes I'm sure its an '87, this was also the last year for 351 4V, which it was, the ID also id's it as an '87

 

Hmmmm,

Not meaning to hijack but regarding post #21.
What does it mean if grounding the diagnostic wire elicits no flash at all from the RABS light on the dash?
I've been staring at this thing for years and would love to fix it.

 

The info I listed in post #2 was CORRECTED in post #13 on May 25th.

Since this was corrected several days ago, you're late to the party.

Try reading all the posts again, before you criticize someone who spends hours of time helping ppl here for free.

I try and post factual info, but can only go by what the parts catalog states in some cases, because I don't know everything

If the parts catalog terminology is wrong, then I'm wrong. Sorry....I'll try and do better next time.

 

I have a 1988 f150, I have had it for about 15 yrs, redone the brakes several times, and the light has always came on after starting, I like you tryed to fix it I just took the bulb out.

 

hey guys. all the answers you have given me were great. if it hadn't been i would have had to quit trying, its just that i hate to have something i cant fix. and without u alls help i couldnt. i am gonna try to find wire and pull codes. if im smart nuff. lol. please dont take offense to what others say because im sure they mean well too. again thanks
bill

 

i will return in a few days to let u all know the outcome
bill

 

i havent gotten around to finding the black wire with orange stripes yet. maybe tomorrow. just another question please?. i unhooked the connector from the sensor on the rear axle. light still stayed on. then i unhooked the plug with 3 wires in it on the master cylinder. the yellow light still stayed on. does this mean that neither one of those plugs have any thing to do with rear abs light? the brake light used to be on too, but after switching the wires on master cylinder around, the brake lights work like they should. on when yoy push the emergency brake down and off when you release them. again thanks
bill

 

When the yellow ABS light is on it means that the computer has detected a fault in the RABS system and has disabled the RABS system. So unplugging any of the sensors or working parts the computer will see this as a fault. I know it is a pain but your best bet is to reconnect everything and find the test wire and count the flashes. This should pinpoint the problem. Plan "B" is to ignore it. A lot of guys will tell you that the RABS system is not much use anyway. The choice is yours.

 

The fastest way to find your problem is to pull the codes and let the Anti-Lock Brake Module tell you why the ABS light is on.

Normal indication when you turn the ignition switch to On would be the ABS indicator light would stay on for about 1 second then go off.

Here's the schematics from a 88. Hopefully the color code of the wiring is the same as your 87.


Lower left shows the 3 wire sensor that detects low pressure in either the front or rear brake system.


The Brake warning indicator goes on.

1) With the ignition switch in Start, to test the bulb. (This connection is closed just before the Starter Relay pulls in).
2) When the brake system has failed (low pressure).
3) When the Parking brake switch closes.



This schematic shows the RABS circuit.