Curt Manufacturing 58987 User manual

58987-INS-RA •04/20/2021 •ECN8140 •PAGE 1 OF 4
INSTALLATION MANUAL
Tools Required
Drill Fishwire
Drill bit, 3/32" Electrical tape
Panel trim
removal tool
Cutting tool
Wiring Location(s)
T5
Product Photo
WARNING
Do not exceed product rating or tow vehicle lamp load rating, whichever is lower.
Maintenance
Periodic inspection of all wires and connections should be performed
to ensure there is no visible damage or loose connections.
Wiring Location Guide*
for Trucks (T)
T1 Behind driver side taillight housing
T2 Behind passenger side taillight housing
T3 Behind driver side rear bumper
T4 Behind center of rear bumper fascia
T5 Behind passenger side rear bumper
T2
T4 T5
T1
T3
* Representative vehicle shown
NOTICE
Before you begin installation, read all instructions thoroughly.
Proper tools will improve the quality of installation and reduce the time required.
All steps must be followed to ensure the product will function properly. Once installed,
test for proper function by using a test light or connecting a properly wired trailer.
Level of Difficulty
Easy
Installation difficulty levels are based on time
and effort involved and may vary depending on
the installer level of expertise, condition of the
vehicle and proper tools and equipment.

58987-INS-RA •04/20/2021 •ECN8140 •PAGE 2 OF 4
Step 1
Locate the vehicle battery and
disconnect the negative battery terminal.
Note: Some vehicles may have a second
battery. Remove this terminal also.
Be sure to fasten this wire down
and away from the battery while
completing the installation process
Step 2
Starting at the rear of the passenger side of
the vehicle, on the inside frame rail, locate the
taillight vehicle connectors. The connectors will
be similar to those on your new custom wiring
product. Separate the connectors from the
taillight housing taking care not to damage the
locking tabs.
Insert the custom wiring end with yellow wire
between the separated connectors. Make sure
the connectors are fully inserted with locking
tabs in place. Loosely zip tie in place.
Step 3
Locate a grounding point such as an existing screw or bolt in the frame of the
vehicle or drill a 3/32"pilot hole. The area should be free from rust, dirt, and paint
(abrasive pad/paper to remove rust and paint). Secure the white ground wire with
the ring terminal on the existing fastener or with the provided ground screw.
CAUTION
Check for miscellaneous items that may be hidden behind or under
any surface before drilling to avoid damage and/or personal injury
NOTICE
Once the custom wiring harness is installed, verify that the harness is functioning
by attaching the 4-flat to any vehicle with functioning trailer lights. The taillights
on the tow vehicle should function along with the taillights on the towing vehicle.

58987-INS-RA •04/20/2021 •ECN8140 •PAGE 3 OF 4
Step 4
On the passenger side of the vehicle, route
the 4-flat along the and above the fame rail
up to the rear of the passenger-side front tire.
Step 5
Using a fishwire, route it down along the inner
fender and outer fender. From under the vehicle,
pull back the inside of the wheel well lining until
you see the fishwire. Feed the 4-flat wire up into
the engine compartment using the fishwire.
How to Fishwire
A) Fish wire is a way to push or pull
an electrical wire through a blind hole.
Make sure the wire is long enough
to stick out on the other side.
Insert the fish wire through the blind
hole and locate it on the other side.
B) Use tape to secure the harness
to the fish wire and pull back up.
The fish wire or harness may get hung up on
something, if this happens you may have to
push back down, wiggle it around or twist the
wire to loosen it from what it's hung up on.
Fish wire could be anything from a cut-up wire
hanger, stiff wire, rope or string depending on
what is needed for the installation.
A A
BB

58987-INS-RA •04/20/2021 •ECN8140 •PAGE 4 OF 4
Step 6
Route the 4-flat along the passenger-side
inner fender to the front of the truck.
Step 7
Secure any excess wire so that it is not drooping or dangling, but not so tight that
it causes unnecessary strain to the wire which could lead to breakage over time.
After removing slack from the 4-flat wire, tighten any zip ties and add as needed.
Use a zip tie to fasten any excess wire to a solid spot along the driver-side inner fender.
Reinstall all items removed during install. If it was disconnected at the beginning of the installation,
reconnect the negative battery terminal. Install the provided 4-flat dust cover to help prevent corrosion.