My Hella ff75's are wired up to my rack as side lights.
I do not have them all on at the same time, just that pair, and the light emitting from the housing is not very bright at all!!!

What is the problem? My wiring is battery power to light and switch and grounding. no relay or fuses...

Can your switch handle all the current flowing through it or is it going to ignite into a non-fused fireball?

There should be a fuse and a relay involved. When you connect your DMM to the wires coming into the housing, what voltage do you read? If you don't own a DMM, how did you determine that ground connection is actually a good ground?

My guess is assuming you have good power connection connection and there's no problems with the lights themselves the problem is the switch thats not rated to handle the current is acting like a resistor. The switch will get hot, melt and the non-fused wire will ignite your KJ into a damage-claim-denied flame. Please wire the lights as directed by the manufacturer. Car fires are no joke, been in two myself.

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