I’m still searching, but could use some help. I have a '94 Ranger, 4L engine, auto, heavy tow package, with 76K. When I bought it at 60K, I corrected all the age related stuff, so it’s reliable and drives like a 3 yo vehicle. Except the cruise control. There truck was before they had a dash light to indicate the unit is on (or off). I don’t think the PO ever used it, and it worked flawlessly for 3 or 4 years.
Starting about 2500 miles ago, it had intermittent problems. The next time I’d dive the cruise worked fine, sometimes it was 2 tries later, until recently. Following the previous discussions here, I checked the brake lights were working and inspected that the brake light switch is attached properly. I did not find other articles online about repairs or test procedures.
I’m hoping someone might know what else to check. Obviously, on a truck this old, it could be most anything even if in great condition. There have been no hacks to the truck. CC is handy, since the ride experience in it and my car is so much different… use CC on both regularly, to avoid excessive high or low speeds on the freeway.
I’m not sure if the cruise is vacuum operated like it was on the 98 Ram I owned, but the vacuum diaphram failed on my truck. At first, it would gradually lose speed while using cruise control. Then as the vacuum leak (inside the diaphram) worsened, cruise no longer worked at all. So check that diaphram and the vac lines (if applicable) like mentioned above.
I might have to check with the dealer… maybe the shop across the street. This one is an oddball.
I just found that Fords are supposed to have a CC release switch attached to the master cylinder, for factory cruise. Normally closed, it is the fail on most. This one doesn’t have one in that location, so maybe Ford decided to relocate the switch on this one truck. I’ll keep looking.
It’s a suspenders and belt thing… cut power to CC when fluid pressure comes on. That’s a good tip.