Why would the right side rear stop and signal lights only come on dim i checked the bulb?

Answer 1

The reason is that not enough current [milliamps, or amps--whichever the bulb requires] is getting through the circuit. The most common cause for this problem is a poor ground. An "open" ground would let no current flow, and the bulb would not light at all. Since there is some glowing of the bulb filament, suggests the poor ground. Another, but less common cause could be that a wire has been partially cut through, reducing current carrying capacity. For example, most automotive wires are not one solid copper conductor, but 7 to 10 smaller conductors within the insulation sheath. The purpose for these stranded wires is to increase flexibility, and if some of the strands break, then the remaining strands can carry some current, possibly allowing the device [bulb or whatever] to continue to function, albeit at reduced current and efficiency. Before trying to search, locate, and correct a partially cut wire, first check the ground wire from the bulb socket to ground. Make sure all connector contacts, wire, and the contact to the body or sheet metal ground point are FREE OF CORROSION, clean and tight. Check for bad ground, or a partial/ high resistance short in light assembly, or anywhere in the circuit.