Precedent - bucket harness missing 48v relay taps

[Adroc3905]

Purchased a used 2014 Precedent with aftermarket light kit/harness already installed (not ultimate w/ horn + signals). The current instrument harness does not have the 4 crimped connect wires (behind dash) for the 48v relay. Hence, no relay installed. What are my options if I want to install brake lights, new harness? Headlights and tailights (all LED) work fine currently w/ and w/o key on. Have the brake switch (hook style) timer and fuse installed....no brake lights. The red and blk/wht wires test 15.5v in footwell, no key in tow. 16v-12v reducer was installed, so unsure why testing 15.5v at footwell (and other places - aux wires).

Any assistance is greatly appreciated.

Thanks

[TahoeDawgZ71]

The bucket harness doesn't have relay connections. The relay connections would be found in the instrument panel harness that comes with the light kit. Some light kits don't have them.

[Adroc3905]

Updated the above.

Pic of instrument harness.

[TahoeDawgZ71]

I can't read the label, what are the two blues, the tan, and the black wires?

[Adroc3905]

Blue and blk wires labeled (to 12v recepticle). They test at 15.4v constant. Spade female connects.

Blue and brwn wires for horn. Bullet connects.

[TahoeDawgZ71]

Ok, that light kit doesn't use a relay for the brake lights.

[Adroc3905]

Hmm, so then w/ the brake switch, timer and fuse properly installed....brake lights should work.

I read 15.5v @ red and blk/wht wires in footwell - no.key. Is the 16v-12v reducer ignition activated, or could I have a bad reducer?

[Sergio]

Everything is fine but unless you have the Turn/Signal switch, You need to complete the signal to the brake lights.

If You look at that unused 9-pin connector in your picture:

Brown wire = +12v when brake switch closes.
White = Driver side brake light.
Yellow = Passenger side brake light.

Just spread the loom behind the 9-pin connector and use some T-Taps to connect the 3 wires together so when the brake switch is pressed the power goes to the rear brake lights.

[Adroc3905]

3-way tap installed. Brake lights work!!!.....regardless of key or tow switch position. That means they stay lit when parking brake engaged, key out. Shouldn't the ignition off = brake lights off?

Is this due to my particular wire harness (Red Hawk) not utilizing the in-dash 48v relay connect?

[Sergio]

The first issue is that a 16v->12v will eventually cause a pack imbalance by discharging/undercharging the 2 batteries tapped for 16v and overcharging the other 4 batteries.

How quickly it happens will depend on how much You use it, so if You find yourself using the 12v power a lot, invest in a 48v->12v reducer.

Your timer should turn the lights OFF after about 5 minutes of the parking brake being pressed.

A relay or 48v reducer activated by the key switch would eliminate the 12v when the key switch is OFF.