Hello and welcome.

It sounds like you may have several problems working against each other. You should probably start with what malfuction codes you are getting from the computer. Even if the "check engine light" doesn't come on, you may still have some diagnostic codes that would help diagnose the issue. A dealership or any parts store that has a code scanner should be able to get you a list. That is if you don't have a code scanner yourself.

As for the issue, the sensors that are used for ABS/cruise-control/braking are the ones at the front wheels and rear differential gear (for 2005) and at the top of the brake pedal. The front ABS sensors (mounted in the hub assembly, much easier to see with the brake discs removed) can become damaged with dirt/water, or simply age. The rear one (mounted to the side of the gear housing) has a tendency to have its wires worn by things rubbing in that area. It can also have the sensor simply go bad with age or exposure.

The brake sensor (at the very top of the pedal behind the lower driver's console) can really mess with things, including not letting you shift gears, use cruise control, have functioning ABS, basically anything that uses your brake pedal as an input. If that one is going bad, it should be showing up as something like this: P0504 – Brake Switch Circuit “A” / “B” Correlation. It just means the signal coming from the two (redundant) switches inside do not match. This indicates that it's going bad or there's a bad electrical connection. Usually the former unless you've been hacking around under your dashboard.

Dan