Cruise control light is on but won't hold speed. Any ideas?

[wseeloff]

I have a 99 F250 SD. The cruise light comes on the dash but it won't hold the speed. Does anyone know if this system is vacuum or electronic control?

[Stealthee]

I can't tell you how it is controlled, but I know the F250 I drove for work a few years back had issues with the cruise. I would have to try several times to get it to engage. When I would have to stop at tolls booths I had to repeat the multiple attempts to engage it.

It always seemed to me I had to be holding the speed myself for a certain amount of time before it wanted to take over.

[65comet]

There are two brake related cut outs to disengage the cruise for this truck. The switch on the brake pedal and a pressure switch on the master brake cylinder. I know 98 and possibly 99 had a recall on the pressure switch and instead of going with a new switch they installed an inline fuse to handle electrical overload caused by the switch leaking brake fluid and shorting causing a fire. This inline fuse is known to go bad and cause your symptoms. The best solution is to buy a new complete switch. The new one will not leak and recommends removal of the no longer needed fuse as it leads to other problems.

[wseeloff]

Originally Posted by 65comet

There are two brake related cut outs to disengage the cruise for this truck. The switch on the brake pedal and a pressure switch on the master brake cylinder. I know 98 and possibly 99 had a recall on the pressure switch and instead of going with a new switch they installed an inline fuse to handle electrical overload caused by the switch leaking brake fluid and shorting causing a fire. This inline fuse is known to go bad and cause your symptoms. The best solution is to buy a new complete switch. The new one will not leak and recommends removal of the no longer needed fuse as it leads to other problems.

I'll check them out. When I tap the brake the light on the dash goes out so I think that is working. I'll check the pressure switch. Thanks for the input.