Originally Posted by amirie
We have bulbs.. Not LED we checked the two rear bulbs each side and a couple of the small marker lights. Bulbs are fine.
The handy thing about traditional bulbs is that when you pull them out of the socket, you have access to test for voltage there.
If you do see voltage there, either the bulb is not as good as it seems (but it's unlikely all are bad), or the contact is bad. More likely you don't see voltage, and you're looking at wiring (or the connection to the wiring from the tug) for the fault.
Troubleshooting is often an exercise is narrowing down the location of the problem until the only part left is the one which is faulty.