because before they were not dim
The heater could be drawing too much power or your alternator isn't producing enough.
how do i turn off the headlights of my toyota 4 runner 2000 while the car is off?
INSIDE THE HEATER BOX BEHIND THE GLOVE COMPARTMENT.
You may have a clogged heater core, or a leak in the system somewhere. Take your car to a mechanic who can replace the heater core or diagnose the leak.
To adjust a 2000 Toyota Celica headlight prop the hood open. Located the headlight adjustment screws and tight or loosen to fit the appropriate height settings for maximum visibility.
Check your fuses.
To adjust the headlights on a 2000 Toyota Echo, first park the car on a level surface about 25 feet from a wall. Turn on the headlights and mark the center of the light beams on the wall with tape. Locate the adjustment screws on the headlight assembly—typically, there are two, one for vertical and one for horizontal adjustment. Use a screwdriver to turn the screws until the beams align with the tape marks, ensuring they are at the correct height and angle.
The AC switch operates the AC compressor and should have no bearing on your heater function. If your heater is not working properly, you may have a weak thermostat.
To remove the headlights on a 2000 Toyota Echo, start by opening the hood and locating the headlight assembly. Remove the screws or bolts securing the headlight assembly, usually found on the top and side of the unit. Once the screws are removed, gently pull the headlight assembly forward to access the wiring harness at the back; disconnect the harness. Finally, you can replace or repair the headlight as needed.
the dash and radio lights are supposed to dim when the headlights come on. Make sure you have the brightness of the dash lights turned up as much as possible.
To change the heater core on a 2000 Toyota Celica GT, first disconnect the negative battery terminal and drain the coolant. Remove the dashboard and the center console to access the heater core housing, followed by disconnecting the hoses and any electrical connectors. Then, unbolt the heater core from its mounting and replace it with a new one, reassembling everything in reverse order and refilling the coolant. Ensure there are no leaks before reconnecting the battery and testing the heating system.
Flushing sometimes frees up mineral deposits that then clog up your heater core. My mechanic told me to never flush a Toyota as the heater core was low in the engine. That is, only drain and fill when doing a coolant change to prevent dislodging the deposits.
There are two possibilities. First one is damaged wiring. Second one is a burned fuse.