zachnoel

i can not figure what is setting off both the rear anti lock light and the brake light. and since i am taking a trip up to the snow soon i would like to have some anti lock brakes! to start its a 89 f150 xlt 4x4 4.9L. i have already changed the speed sensor on the rear differential and the wires to the sensor seem good. i have ran the codes and i got code 67 and 111 which i believe are pass codes. where is the next place to troubleshoot this problem??

wde3477

Welcome to the site!

Hmm, new territory for me - haven't had to mess with the ABS system - but we'll give 'er a spin anyways.

There is a flashout code sequence - and the trusty Chilton's manual describes just about everything one would want to know - except for how to run the test. Aargh. At any rate - the codes range from 1 to 15 light flashes. So wondering here, did you read the engine management computer or the RABS computer codes?

Eh, at any rate - for the problem you describe - both the ABS and the brake lamps on - some causes listed are:
Low brake fluid in master cylinder
Master cylinder float has lost buoyancy or is stuck
RABS diode/resistor element has failed
Short in brake light wiring

My money would be on a low fluid level or a stuck / failed float in the master cylinder reservoir.

From there, the diagnostics get into the flashout codes. If you can get the flashout codes - I'd be glad to look it up for you, or maybe it's available online somewhere. When you get to that level, the diagnostic procedure gets rather complicated to punch all of it in here.

Good luck, and keep us posted.

zachnoel

thanks for the quick reply! i must have read the engine codes than... how would i go about checking the RABS codes without a scanner?

the master cylinder float you mentioned, is that the sensor on the bottom of the brake fluid tank?

i have also looked all over for a wiring diagram for the RABS, do you know of any links to where i could get that info?

thanks

Just call me Sean

iTrader: (1)

When the "brake" light comes on the "ABS" light automatically comes on. It doesn't mean a problem with the ABS, it's just how the lights work. When the "ABS" light is on without the "brake" light then it's a problem with the ABS. Low fluid level or air in the lines is more than likely your problem. Code 67 is manual lever position sensor out of range, which means that the sensor that tells the computer what gear the transmission is in isn't working right. Unless it's a stick, then it means clutch switch circuit failure, which is the sensor that tells the computer when you have the clutch pedal pressed in. Code 111 is pass.

zachnoel

so you think there is a problem with the parking brake switch?

zachnoel

got the rabs code = 4

how to... http://autorepair.about.com/library/a/1g/bl583g.htm

zachnoel

is there a fix to the code 4?