03 T&C steering

If I travel a distance of 50+ miles in one trip and if I turn the steering makes a horrendous noise...around town short distances it does not do anything though.

Also the sliding door does not automatically open if it is cold outside, the dealer seems not to know how to take are of either situation

If it's a sqealing noise you may have a worn or loose pump drivebelt. If it's a moaning noise you may have a bad pump, contaminated fluid, pinched hose, clogged strainer (if there is one) etc. There's no magic bullet. It needs to be looked at by someone with some knowledge.

If you're a DIYer the first thing I would do is drain and replace the fluid. How? Either disconnect the hose at the pump leading from the reservoir or use a turkey baster and suck the reservoir dry 4 times, driving it between fills. Still squeals? Change the belt. Still squeals? Change the pump.

Never touched a powered side door but, basics are basics. Make sure the tracks and lock mechanism are clean and lubed. Beyond that it may need adjusting or the drive motor may be getting weak.

check fluid level if okay and is a BRIGHT red put a rack in it the sliding door dont work when its cold or just stopped working alot of the time the wires get pinched in the plastic chain at the bottom track with in 3 inches of where it pins to the door arm/hinge/roller (inside the plastic chain)

by the way find a new dealer