BX8848 Installation Instructions
4 Diode Wiring Kit
For Motorhomes With Amber Turn Signals
292-1305
Rev.
D
Page
3
of
5
4/11/12
Overview: Run the four wire harness from the front of the car to the back seat of the car. Identify the proper wires on the
car wire harness under the back seat and splice in the diode modules. Hook the four wire harness into the diodes.
1. Decide where you want the plug of the wiring kit harness to stick out of the front of the car. This will be hooked/
unhooked each time you hook/unhook your tow bar, so find a place that is convenient for you. The four wire plug will
need to be cut off and the six pin trailer plug substituted. Mounts for the trailer plug are not provided. A metal bracket
could be attached to the baseplate or a hole could be drilled in the bumper cover and the plug bolted into the cover.
2. On the driver’s side of the fire wall there is a large rubber grommet where the main wire harness enters the passenger
compartment. The wiring kit harness will also enter the passenger compartment through this grommet. The grommet
is located directly behind the steering wheel and dash in the passenger compartment.
3. Route the wiring from the plug location back to the grommet in the fire wall. Be sure to keep the wire away from
moving parts and areas that will get hot while the car is running.
4. Using a utility knife or a sharp pocket knife, cut a slit in the grommet just big enough to push the end of the wire
through into the passenger compartment. The smaller the slit the better, so don’t make it any bigger than needed.
5. Push about 12” of wire through into the passenger compartment. Locate the wire behind the dash and pull the rest
of the wire through into the passenger compartment, leaving plenty of slack in the engine compartment to tie the wire
harness down and still leave the plug in the desired position.
6. Along the threshold of the driver’s side door there is a piece of plastic that holds the carpet down. The plastic snaps
into the metal frame. Starting near the center post, pull up the plastic and unsnap it from the metal frame. The plastic
narrows and continues up around the door. Do not pull this part of the plastic loose.
7. The carpet ends behind and above the brake pedal. Feed the wire harness behind the carpet and down to the
threshold of the door. Pull all the wire down to this point. Lay the wire under the carpet back to the center post.
8. The bottom of the back seat is held down by two steel clips. The clips are located along the front of the seat and
would be between your legs if you were sitting in the seat. Slide your finger or a small screwdriver along the seam
between the seat and the floor to locate the exact position. To release the clip push in on the clip with a screwdriver.
With both clips released, pull the front of the seat up and remove the seat.
9. The back door threshold is similar to the front. Pull up the threshold to gain access under the carpet. Run the wire
harness around the center post (you may need a piece of stiff wire to help push the wire through) and along the back
door and into the back seat area. Replace the carpet and thresholds.
10. Under the driver’s side of the back seat there is a plastic loom. Open the loom and pull out the wires. You will find
several light blue colored wires. Some of these wires are used for the left, right, and center brake lights. Have
someone step on the brakes and use a needle point tester to determine which wires are used for the brakes. The
others may be “hot” when the stereo is on, so the stereo system must be shut off while you are identifying wires.
11. When you have identified the brake wires, strip the ends and crimp on a male spade terminal on the end of the
wire from the front of the car and a female spade terminal on the end running to the back of the car. Plug the male
terminal into the “in” side of the diode block and the female terminal into the “out” side of the diode. Try the brakes to
make sure the lights work.
12. Cut any excess wire off of the four wire harness. Leave about 6 to 8 inches of slack. Separate the four wires. Start
on the outside and carefully peel each wire back about 6 inches. Inspect each wire to make sure there aren’t any
bare spots showing. Wrap any bare spots with electrical tape. Strip each wire and crimp a male spade terminal on
each wire. Plug the white wire into the brake diode block.