Would like to hard wire my saturn to my motorhome for signal lights,brake lights,park lights

NOT ABS lamp , right?
the parking brake is adjusted first pre the service manual then
the switch must be adjusted to for closure brake released;
i use volt meter that switch after install and make sure it works
if not RTM read the service manual , on topic

this care is ODD
see this chapter in the service manual if opted day1.

Electronic Parking Brake Description tip if ice berg

Vehicles with the electric parking brake have a switch in the center console, which takes the place of the manual parking brake system, the foot pedal and release handle. In case of insufficient electrical power, the electric parking brake cannot be applied or released.
Occasionally, the electronic parking brake will automatically apply when the vehicle is not moving. The electronic parking brake performs a operational check every 50 key cycles. When this check is being performed, the park brake light on the instrument cluster becomes illuminated. This function does not affect the normal operation of the vehicle.
Electric Parking Brake Control Module The parking brake control module has an internal motor, apply actuator, release actuator, and temperature sensor. The parking brake control module also contains the logic for applying and releasing the parking brake when commanded by the park brake control switch. When the parking brake control module receives a signal from the switch the internal circuit board temperature is checked to verify it is within operating range before the control module performs the requested operation.
The electric parking brake module receives hard wired signals from the apply/release switch and communication enable. The electric parking brake module receives wheel speed sensor signals, engine torque, gear information, brake pedal signal, and etc. through GM-LAN.

AND MORE, LOTS MORE, READ THE MANUAL
PAY LIKE i MUST.

https://eautorepair.net/Marketing/Default.asp

https://s8.postimg.org/ew3ed6k85/saturn_aura_stop_lamps.jpg

You may have a bcm problem? The bcm controls both the brakes and turn signals. Any applicable trouble codes? Click on the link, part of wiring for brake lamps, you can check the fuse and relay. Also, check the fuse circuit for voltage, use a test light.

They might. The shift interlock solenoid is controlled by the brake light switch. When the brake pedal is depressed the switch sends a signal to the interlock solenoid attached to the shifter assembly to allow it to release. Check to see if the brake lights are operational. If not, suspect a problem with the brake light switch. If brake lights are working, possible wiring to shift interlock solenoid or solenoid itself causing the problem. Your vehicle may be equipped with an interlock release button located close to the shifter to allow it to come out of park that can be depressed to release the shifter. Owners manual may provide more information on this procedure

On most models the brake light circuit runs thru the turn signal switch. The third brake light does not. So it could be a problem with the turn signal switch.
A ground problem would also affect the parking lights.

Best thing to do is get a 12 volt test light.. check all the wires on the vehicle to make sure all power is coming threw to the back For signals the test light will flash like a signal.. Break wire will work like brake light on tester same with park lights, if you have power to all plugs on vehicle test the front wires first if there is power move back a ways and test again. till you get to the rear if there is a bad spot in a wire the light will not illuminate. thats your bad spot, The next thing is the plug in it self check it for corrosion pulled out connectors corroded wires. plugs go bad..If your not familar how to do it its easy, and ive included a video to show you.. Check your bulds hold them up to light and see if the elements are being burned if so signs of a short. if elements are good then no power is getting to them
Precise Engine Repair Notebook

Check the brake light switch on the brake pedal. Sounds like it slipped out of adjustment. When pedal is depressed, the button on switch will extend and be on to pass current to the bulbs.
Also, you need to figure out the tail lights: those two filament bulbs are for park lights and for brakes/turn signals. One filament is for the parks, the other filament is for both brake and turn signals. American cars have the brake lights wired through the turn signal switch- from the brake light switch on the brake pedal to the turn switch, and then out to the rear bulbs for brakes and, or turn signals.

Yes I would look for a ground circuit problem. I would look at the ground wires for the headlights first. Even run a new ground wire for the tail lights to see if it helps.
Could be a ground connection for the body to frame or body to battery.

It's called Brake Fluid Level Switch Try a auto salvage yard > Couple of buck's
Brake System Indicator
The instrument panel cluster (IPC) illuminates the brake indicator when the following occurs:
• The body control module (BCM) detects that the park brake is engaged. The IPC receives a class 2 message from the BCM requesting illumination. If the vehicle is shifted out of park with the park brake engaged, the BCM activates an audible warning.
• The body control module (BCM) detects a low brake fluid condition (signal circuit is low). The IPC receives a class 2 message from the BCM requesting illumination.
• The IPC detects a low brake fluid condition (signal circuit is low).
• The IPC performs the displays test at the start of each ignition cycle. The indicator illuminates for approximately 3 seconds.

Check your brake fluid. The same light is used for the brake fluid level as well as the parking brake.

directly to tail lights in trunk with a four pin attached to car light wires and then u run long seet of wires with male at one end and female other end and connect when needed to connector in trunk and to receiver connector