Hello everyone,

I have been trying to get my Piaa 1500xt Back Up Lights to work. I thought it was the relay, so I called Piaa and they sent me a new one because we thought that was the problem. It's not.

My situation is a bit strange. The switch and the relay are both functioning properly, but the only time the light works, is when I step down on the brakes really hard. I don't know why. It should not even affect the function of the lights, but the lights only come one when the brakes are fully depressed. The wiring is direct to the battery and the ground is to the chassis and I've triple checked everything. I just can't figure out how the brakes come into play here. Can anyone please help me out?

What are you using to signal your relay (low amperage 12v side)? Did you somehow tap into the brake light circuit? Is this a circuit that you want to come on when in reverse, or is this a completely independent circuit that you simply have a toggle switch for?

- Jim

My friend does car stereo installation and he found the "Reverse Light" wire and tapped into that for the switch, to signal the relay when i'm in "reverse" mode.
I'm trying to install extra back up lights into my new Darlington HD bumper. I have checked everything and none of the wires are even connected to the car's electrical system. Checked every inch of the wiring. The piaa switch has two options, 1. Turn on lights anytime, and 2. Turn on lights when reverse lights are on. I tapped into the reverse light wiring in the front dash, but that does not seem to be the problem. Because, even if you don't use that tapped wire for the reverse lights, the constant "ON" should work for one side of the switch. The only wierd variable is that, when i start the car, it doesn't work. But when the car is turn off and I press down on the brakes. the lights work. Same for when I back up, if i have it set to turn on with the reverse lights, they only turn on when i step on the brakes hard, but if i step on it lightly, like when you are backing up, it will not come on....Any ideas? Please help, I'm still trying to fix the problem right now....

Did you check it out where your buddy tapped into the reverse light wire? Is there something frayed in the wires around it? Did he tap into the wire running to the bulbs or is it some other wire? Are you sure he got the right wire?

Jay <img src="/forums/images/graemlins/mrt.gif" alt="" />

Yes, We followed the reverse light wiring from tbe back all the way under the floor board of the driver seat. He used one of those clamps that splices into the wire. It's a clean tap. Even when I unplug that wire and only use the Constant "ON" side of the switch, it still only turns one when I step down hard on the brakes. But nothing is connected internally to the vehicle's electrical system. The Power came straight from the battery and the ground is on the chassis.

I dont know if this is the problem but here is a tip. Isuzu seems to like to use switches on the GROUND side of the device instead of the 12v side like most other cars.

After having that much trouble, if it were *ME*, I'd probably remove absolutely everything and start 100% from scratch - including NOT using that same line-in blade connection.

As much as I'm sure that you don't want to, doing so might save quite a bit of time (and headaches) in the long-run.


No matter what you choose to do - Best of luck!

<img src="/forums/images/graemlins/cheers.gif" alt="" />
<img src="/forums/images/graemlins/smile.gif" alt="" />

I'm baffled by this problem and will probably have to pull it all out and start over. It sucks to have to fish the wires though the entire truck again...

You need to draw a diagram of what you have installed with the connections you have made and methodically move through the circuit identifying where and when power is applied. I am guessing your brake light wire is wired to be your source of power directly to the lights. This is not rocket science so don't get overwhelmed just be methodical and disconnect things and probe for 12V with a multimeter or test light. You don't have to remove anything from the vehicle but you should start by disconnecting everything.

Woo Hoo!!! Finally got it working correctly. This has been a thorn in my side for about a month already. My power source and tap into the reverse lights were fine. The problem was the ground on the rear Chassis. The two piaa lights were ground to the chassis in the rear, Looks like a normal ground to the metal part of the frame. But I don't know why it didn't work correctly. After taking apart all the other connections and testing each one, I found that the only thing it could be was the Ground for the lights that were on the rear bumper. So I ran a large wire from the (-) on my battery and connect it to the two ground wires from the light. IT WORKS! I think when I step on the brakes really hard, a metal part of it must be touching the chassis completing the circuit. Not really sure why it works know, but the only thing I changed was running the ground wire from the rear lights all the way to the battery instead of grounding it to the frame of the vehicle. As of right now, everything seems to be working, but I wouldn't be surprised if it stopped working again tomorrow.

THANK YOU everyone for you help and input.