06 Precedent Brake Lights Relay Failure

[Doug Stuart]

I have an 06 48v Precedent that has blown through two relay switches for the rear brake lights. The horn also stopped working, but I am not sure if it is related. The cart has 4/12v setup and the lights are factory tied to one 12v source.

The kit is a Rec Pro LED and has worked perfect for the last year. It is tied into the factory wiring harness and I have both +12v and -12v at the relay. When I bypass the relay the brake light system works fine. Timer works as it is supposed to, although I am not sure what the 4th (blue/white) wire is feeding off of the relay.

As for the horn, I have checked continuity on the switch and wiring and both are good. Again, not sure if it is tied into the 4th wire on the relay.

Upon initially checking all connections I found that the +12 lead to the brake light switch was loose and corrected that issue. The system came to life and worked for a few minutes before I noticed the relay getting warm...not hot, just warm. That is when it stopped working.

I have checked the relay with an ohm meter and there is no resistance in the circuit. I also do not hear any clicking upon charging it with 12v so I am pretty certain that the second relay is toast.

I am stumped as to what may be causing this issue.

Any input or thoughts would be greatly appreciated as relays can get expensive.

[Muddog]

Are you using a 48 volt relay?

[Doug Stuart]

Yes. The same relay as in the Madjax Ultimate light kits and usednin the chargers.

[Muddog]

What is activation voltage of relay? It is most likely 48v, you are putting 12v to it, it is having to much current run thru it. That's why they are failing.
The relay is used on 6 8v battery pack.
The brake light activation circuit is 48v, so you need relay to activate 12v brake lights.
You don't need relay when brake light circuit is connected to 12v source on 4 12v setup.

[Doug Stuart]

Thanks! That does make perfect sense, but I was hesitant because I didn’t understand the “why” behind the relay. Now to figure out what the fourth wire is there for.

[DIYwhenIcan]

Having same issue as Doug and have exact same 48v 4 battery setup with lighting system tied to one of the 12v batteries. After a few months, brake lights don't come on anymore. Delay timer is likely toast. Not sure I understand the answer. I don't need the timer when tied to a 12v battery?

[Sergio]

Using a single battery for accessories is not good for the entire pack in the long term.

If You do decide to use a single battery (or 2 x 8v for that matter) on a precedent, You have to start from pack negative.

In your case, 4 x 12v batteries, you must use the pack negative battery to provide 12v or you will have problems (back feeding power to the key switch when it is OFF).

The relay is important when using a constant 12v source (like a battery) so the brake circuit does not consume power when the key switch is OFF (the relay interrupts the 12v).

if You are using a 48v->12v converter that turns ON/OFF with the key switch, they the relay is redundant and You can just jump together the 2 x 1/4" quick connectors by the relay behind the dash. Don't mess with the smaller 2 x 3/16" quick connectors as they are switched 48v from the key switch.

[DIYwhenIcan]

OK, that is starting to sink into my head. The instructions with the light kit install were vague but implied to me to just use the timer relay with one 12v battery and other Internet information said just make sure you rotated which battery you tapped off of every month or two. Some of these 48v to 12v converters cost no more than that failed timer. Can you steer me to a quality converter vs. the junk ones, or am I on my own? Thanks!!

[Sergio]

The relay and the timer serve different purposes and you can decide if You need them or not depending on your situation.

The timers purpose is for when the parking brake is applied and the key switch is ON, unless you have a pressure switch on the pedal surface or a second switch mounted to disable the brakes when the parking brake is applied, the brake lights would stay ON.



I don't use a timer with my cart since it would be unlikely for the brakes to be left ON with the key switch ON and not noticed since I also have DRL Leds on the front of the cart.

There are good options from site sponsors, for a Precedent www.revolutiongolfcars.com sells a plug and play converter that mounts up front and taps into the existing harness.

If You plan to add a Radio or other accessory that would require some constant power, www.cartsunlimited.net sells a converter that has both switched 12v and constant 12 outputs.

Either one of those also turns ON/OFF with the key switch so You can just by-pass the relay connection on the dash by connecting the 2 x 1/4" female quick connectors together using an automotive style blade fuse (5 amps).