2003 No rear passenger brake/turn signal light. Already replaced MFS/Connector

[evolver]

So have a fast blinking front passenger turn signal and no rear turn signal or brake light. I do have rear driving lights though.

I replaced the MFS and grey connector as the old ones pins were out, thought that would have solved it but no go. If I swap the two wires on the smaller side of the gray connector the turn signals are reversed. Now I get a steady slow signal light on the passenger side but still no rear brake light.

So I guess I'm looking at a bad wire somewhere past the MFS? How to I check to see if its the ground or the positive connection to the signal/brake bulb? If the driving light lights up wouldn't that mean the ground the the turn signal bulb is ok?

 

[evolver]

So have a fast blinking front passenger turn signal and no rear turn signal or brake light. I do have rear driving lights though.

I replaced the MFS and grey connector as the old ones pins were out, thought that would have solved it but no go. If I swap the two wires on the smaller side of the gray connector the turn signals are reversed. Now I get a steady slow signal light on the passenger side but still no rear brake light.

So I guess I'm looking at a bad wire somewhere past the MFS? How to I check to see if its the ground or the positive connection to the signal/brake bulb? If the driving light lights up wouldn't that mean the ground the the turn signal bulb is ok?

Ok so I disconnected the plug and took the brake light bulb/holder and jumped it to the female adapter under the bed With the left turn signal the light bulb works and blinks. With the pins connected for the right turn the light bulb is off.

If I use a light probe, it lights up and beeps normal steady speed for left turn signal and beeps fast for the light turn signal. My multi meter battery is dead so I couldn't test how much voltage is on the broken side but beep and light were quieter and dimmer then when testing the left side.

Can I try to activate the turn signals with out the MFS but jumping wires to see its the replacement MFS (used) or a wire issue?