EMS/Police Lightbar conversion

[mushroomsatsujin]

I have a few lightbars taken from police vehicles (legally). One is a long lightbar that goes on top and I know it takes 12v. This really isnt unlike any other led project so Im hoping I can get some insight on this. I have a 12v power source but the wires are different gauges. I cut the end part of the power source to combine the two wires of the components but Im not even getting any readings off my multimeter when I plug the power source up. Ive tried multiple 12v sources and none seem to work. My goal is to be able to attach them to a home outlet.

:Im familiar with some electronics but Im still very new

 

[KJ6EAD]

Light bars often require more amperage than you'd guess so it's possible that your supply is too weak, or you may have the wrong polarity or some other wiring error.

 

[shrtrnd]

My brother bought some of these light bars from a local police auction. First-off you should know that they weren't just traded-in for replacements by the police department for no reason.
They're typically defective in some way, and that's why they were taken out of service.
You may be wiring them up correctly, and are just seeing the defect that caused them to be taken out of service in the first place.
I'd be looking for any circuit boards inside the light bar that may need repair. (Or burned components or wiring).
Good luck, they'll be bright and impressive when you isolate the problem.
If they're not straight LED activation, and have motors to rotate light reflectors, you'll need to take a VERY serious look at those first.
The motor/motors might have burned-out or open-circuited.