No brake lights!!!

[99TransAm]

I just bought the truck and did not realize that the brake light didn't work until I got home. The cab/third brake light works but the two on the bed do not, also the left blinker and the right running light does not work. I checked all the fuses and found 1 burnt out and replaced it, but nothing changed. I replace the turn lever because I heard that was a common problem but nothing changed. This in on a 2002 GMC 2500HD

[Danthaman69]

Check the connector under the bed. That goes bad too. Its cheap. Has 4-5 connectors on it.

[99TransAm]

Check the connector under the bed. That goes bad too. Its cheap. Has 4-5 connectors on it.

I already checked that, pulled the connections and cleaned them. Is there a way to replace the entire piece?

[oldscsc]

First, check all the bulbs in question. Let us know what works after that.

 

As for diagnosis, if you can't get a wiring diagram of the system and properly diagnose it, I would start by removing the grounds for the above circuits, cleaning their mating surface, then reinstalling.

[Danthaman69]

Do you have a multimeter? Try that.

[99TransAm]

Do you have a multimeter? Try that.

 

I tried it on the volts setting and was getting 0 volts at the socket, I dont know where else to test. Also where are the grounds located for these lights, I want to clean them up but cant find them

[oldscsc]

Start at the back of the truck and work forward by checking for voltage present at each connector on the brake signal wire.

 

For example, if you find that you have power going into the junction block but have no power going out, the junction block would be your culprit. If your multimeter is not an auto ranging model, set the meter to DC V on the 20V scale.