Assuming the rear-anti-lock has nothing to do with the cruise control. I was told it might be a thing called the clock spring by a Ford mechanix, he had no time to continue, but does anyone know if this is hard to get to, replace etc. All fuses are new and/or replaced. Also,someone mentioned the speedometer cable, my speedo, fluctuates below 50mph all the time, but this did not seem to effect the cruise before. Is it time to just replace the speedo cable to tranny?Anyhow, Thanks again for the help.
Usually if the clockspring is bad the air bag light will flash 3 blinks then 2. Also your horn wouldn't work. In order to replace you must remove the air bag and steering wheel. I would lean more towards a rabs valve on this vehicle
The 1990 trucks didn't have airbags so no clock spring (that didn't come out before 1992's truck) but it has three contacts that do wear out and a check of the horn could verify if the contacts are bad sometimes. Depending upon the cruise control, If I remember that is the old diaphram style cruise control (electric didn't come out till the 1992 MY) and usually the amplifier (under the dash) or the diaphram busted causing loss of cruise. Check for the brake lights working correctly and their is a deactivation switch somewheres on the brake system that can cause lack of cruise (If I remember it's on the master cylinder and has to have 12v (coming in, going thru the switch and then going out the other wire) for it to work. I can't remember how it picks up speed right now Some used a electrical port that was attached to the speed sensor in the transmission while others used the ABS sensor. (but most used the transmission pre 4WABS if I remember) The speedometer problem is from either the cable or the speedometer head itself usually (sometimes the gear in the tranny does mess up however) Ford used a tester to hook up in line to check the amplifier and diaphram on those. you may need to find a dealer with one willing to look at your truck.
