Hello all,
Thank you for your help on the issue I recently posted about, got that all fixed up and solved.

I am having some problems with my cruise control (referred to as "speed control" in manuals). Cruise control does NOT show up on dash when activated AND does not control speed. I tried multiple times on the highway to engage and disengage it. I went through the process of checking fuses (both under dash and in engine) and checking all vacuum lines and electrical. Truck is originally equipped with speed control, it is not after market.

With everything seeming fine, I cannot figure out what the issue is. My only assumption is that the buttons on the wheel need replacing OR something is wrong that I cannot visibly find. Again, speed control is not showing up on dash when activated.

I have seen in some vids on YT that on the brake master cylinder is a sensor that taps out and will cause this issue.

Thank you again for the help from the members that replied on my last post. You saved me big time/

- Johnny

 

Apologies, I want to ensure I understand, what is the third brake light, are you referring to the one on the top of the cab? And where are speed sensors generally located?

When I purchased the truck, I noticed a few buttons in the door pocket (generally window switches). Can the button be a culprit? I am trying to learn more about diagnosing electrical problems lately and doing some studying up on the basics of electrical engineering.

 

Given that you find all else is working, on my 96, (250,000 miles), the buttons on the steering wheel are the problem. Ours are old enough now that these parts have been very elusive for me to find.
My 96 does not have a dash indicator for the Cruise Control, which I found to be strange. I've had the dash out of the pickup several times replacing instrument lights There is no reference to it in the OEM owner's manual I have, and I see nothing on the printed circuit film /back of dash and there is no instrument light for it. Nothing anywhere shows up on the key on tests. You set it and if you feel the fuel pedal move, or you take your foot off of it and speed is maintained you know it is on. I can set the cruise control and I can resume the cruis most of the time. However, the 'coast' /speed increase/decrease function does not work. Well, the increase oes work but it works with both the + and -, increasing speed one half mile per hour for each push of either button.

What is strange is that while there is no Cruise light, tt has an airbag light that only comes on during the key on tests, but never had airbags! The Ford stealership service writer told me this pickup never had an airbag option, but the light was generic to the dash makeup on several models that did. He couldn't explain why the same didn't apply to a dash light for the cruise control..

 

I have seen some sources also citing some sensor on the brake master cylinder that goes bad OR stops working when brake fluid is low. Though, the info is for 94 to 02 F250. I will check Haynes manual to see and i will also check 3 brake light (cab light)