Bed light wiring help, please

I’m trying to finalize my bed light install and having some issues. I’m not too experienced on electrical, so please excuse my ignorance.

I did find the correct wires to tie into my cargo switch. My problem is when I try to hook up more than one light, the lights are very dim and the cargo light cuts out. I have a positive and a negative coming from the cargo lights. The 1st pic is 1 of the 4 bed lights I’m looking to install.

If I hook the positive (red) from the cargo switch to the red on my rock light and the negative (black)from the cargo switch to the negative of the rock light, it’s super bright and the cargo light stays let. If I try to tie any other lights in, they dim very low and the cargo light shuts off.

Any tips for a newbie on how to properly install all 4 lights?

 

@RowdyRon

 

Sounds strange. But first off, don't ground to the switch. Find a good ground to the body. There's one behind the cover, driver side, lower left.

 

The 1st pic here is where my positive (red) wire is hooked. And the 2nd pic the wire (black) is hooked up there. Those are the two wires that run back to my lights. I’m assuming the black is the ground, but maybe that’s wrong?

 

I'm not very good with electrical stuff but if you're able to hook up one light successfully, and additional lights are causing dimming, my guess is you're drawing too much power from that circuit. I estimate your lights are 9w and only draw .35 amps each so I'm a little surprised.

So, the solution would be to use a relay. You use the + wire from the cargo light circuit as the trigger (pin 86)
pin 87 to the lights. pin 30 fused from the battery. 85 can be grounded in the engine bay.
Your lights (black) can be grounded to the ground bolt behind driver side kick panel.