My 1999 f250 super duty has rear abs only and the abs light comes on when I get to 20 mph the when I shut the truck off it resets. once I restart and get moving again at 20 mph it happens again and the cruise control also is not working. I have replaced the sensor on the rear and the pigtail with no luck. The fuses are good. The brake light switch has been replaced for a different issue and immediately this started but that should be unrelated.

 

If only everything was that simple.

When you step on the brake pedal it is supposed to open the circuit for the cruise control and cancel the request.
If for instance the stoplight switch is misadjusted, it can prevent the cruise from working by preventing the circuit from closing and thereby cancelling the cruise request.
Just one possibility.
If the ABS system is not receiving the correct info it can set off a fault and cause the ABS light to illuminate. There could very well be a wiring problem and it will require someone to thoroughly check the system.

 

would you know if the GEM might cause such a thing to be happening? i have had it be a issue at times after rain.

 

It's possible, but confirmation of everything getting the right info and communicating it to the proper place will need to be checked.
Without a thorough check of correct ABS info getting to the proper place is like flying in a fog.
Certain problems did originate with the GEM module getting moisture contamination, but the module should be checked first before jumping to any conclusions.

 

i understand. it is just odd that everything worked correctly before changing the brake light switch. that was replaced due to the third brake light not working which i did not even realize cause I had a camper top on it since new.