THECARRIERSTANDARD.COM
4-PIN VS. 7-PIN: VEHICLE / TRAILER COMPATIBILITY WORKSHEET
US / NORTH AMERICAN CONNECTORS. Stationary check only.
Not a certification of trailer braking, wiring safety or legal compliance.

DATE: ____________   PERSON CHECKING: _______________________________
TOW VEHICLE YEAR / MAKE / MODEL: ______________________________________
TRAILER ID / TYPE: ___________________________________________________

1) IDENTIFY PHYSICAL CONNECTORS (do not force mismatched plugs)
Vehicle socket: [ ] 4-way flat [ ] 7-way RV blade [ ] 7-way round-pin
                [ ] 5-way flat  [ ] Other / not identified: __________
Trailer plug:   [ ] 4-way flat [ ] 7-way RV blade [ ] 7-way round-pin
                [ ] 5-way flat  [ ] Other / not identified: __________
Adapter required? [ ] No  [ ] Yes   Exact adapter part no.: __________

2) WHAT DOES THIS TRAILER ACTUALLY USE?
[ ] Running / marker / tail lamps       [ ] Left stop / turn lamp
[ ] Right stop / turn lamp             [ ] Electric trailer brakes
[ ] Reverse lamps / reverse lockout    [ ] Auxiliary +12V supply
[ ] Other functions: _________________________________________________
Trailer manual / equipment specification checked? [ ] Yes [ ] No

3) WHAT DOES THE TOW VEHICLE ACTUALLY SUPPLY?
[ ] Correct basic lighting outputs checked
[ ] Electric brake controller installed/configured, if needed
[ ] Brake-controller output verified by approved method, if needed
[ ] Appropriate auxiliary / reverse circuit confirmed, if needed
[ ] Vehicle / connector / trailer instructions consulted
Documentation used: __________________________________________________

4) ADAPTER DECISION (circle YES / NO / UNKNOWN)
Does connector shape physically fit?                YES / NO / UNKNOWN
Does every required lighting function work?        YES / NO / UNKNOWN
Are electric trailer brakes required?              YES / NO / UNKNOWN
If required, are brakes functional and verified?   YES / NO / UNKNOWN
Are auxiliary / reverse functions needed and OK?  YES / NO / UNKNOWN
Any corroded / bent / overheated contacts?          YES / NO / UNKNOWN

5) PRE-TRIP RELEASE CHECK
[ ] Correct plug fully seated, held securely, protected from water
[ ] Cable has turning slack, no dragging or hot/sharp contact
[ ] Running lamps, both indicators and brake lights pass
[ ] Required marker/plate lights pass; hazards checked if fitted
[ ] Required electric trailer brake operation verified separately
[ ] Vehicle/tongue/hitch weights and local requirements checked
[ ] All unresolved problems repaired and retested

UNRESOLVED ISSUE / NEXT ACTION:
_____________________________________________________________________
_____________________________________________________________________
QUALIFIED INSTALLER / RENTAL REPRESENTATIVE: _________________________

STOP: An adapter can make a plug fit without providing brake-controller,
auxiliary-power or other missing circuits. Do not use a trailer with
required lamps or braking functions inoperative or unverified.

Reference reading: CURT towing electrical wiring and adapter guides,
Ford towing connector owner's manual, etrailer ETBC7 installation guide.