Check Engine light flickers occasionally

check all your filters, air and fuel

The trailer might have a bad ground. My camper does the same thing to my truck. Try directly connecting the trailer ground to the frame of your vehicle. This might solve the problem as it did for me.

Check the fuse for the trailer tow parking lamps, this is engine compartment fuse # 5, 20A
The other thing to check is the trailer tow parking lamp relay.

More than likely it's a problem with the wiring. Check the wiring diagram for the trailer again and make sure the wiring is correct. It does seem like a strange problem, but something similar happened to me when I wired my trailer a little loosely on the connectors. Good luck. http://arrowtrailer.com/new.htm

Not sure which fuse you checked.
The Engine Compartment Fuse Panel ( Battery Junction Box / BJB ) is where the fuse is for the trailer tow adapter parking lamps.
Fuse # 5 is the fuse for the parking lamps, and the reversing lamps.

Next is the trailer tow adapter park lamp relay. This is what BJB Fuse #5 feeds, and the coil is operated by the truck's parking lamps. This is also in the BJB, Relay 201, it is the 1/2 size relay.

Not sure what you took a resistance reading from on the trailer tow adapter.

If you want, you can pull the trailer tow park lamp relay, and jumper the normally open contacts, which should provide power at the trailer tow adapters, regardless of the truck's lights.


This is the wiring diagram for the trailer tow park lamps

There are a few fuses for the trailer tow adapter.

1st, is theodd location on the 97-98, engine mini fuse panel has a 20 A fuse forthe stop / turn lamps. Have seen it covered in tape from the factory onsome 97-98 MY trucks.
This is on page 142 in the owners 1997 manual, all the revisions for the 1998 owners manual I have seen do not include this fuse box for some reason.

Download a PDF version from Ford, for the 1997 MY at :

https://www.fleet.ford.com/maintenance/owners_manuals/default.asp

This is a picture of the Power Distribution Box, additional relay box and engine mini fuse panel with the covers off. The 20A in the upper right panel with the red base, is the trailer stop/turn fuse.


The others :
1. Power Distribution Panel / engine compartment fuse panel
Fuse #1 - Trailer tow back-up and tail lamps
Fuse #16 - Trailer tow battery charge and stop/turn lamps
Fuse #28 - Trailer tow electronic brake

2. Instrument Panel Fuses ( cab fuse panel by hood release )
#23 - trailer tow battery charge relay

does every work properly with the wiring to the trialer disconnected? (un hook the wiring to trailer and put back the way it was) and let me know

As listed in the owners manual.

Weight of the Trailer
How heavy can a trailer safely be?
It depends on how you plan to use your rig. For
example, speed, altitude, road grades, outside
temperature and how much your vehicle is used to
pull a trailer are all important. It can also depend
on any special equipment that you have on
your vehicle, and the amount of tongue weight the
vehicle can carry. See “Weight of the Trailer
Tongue” later in this section for more information.
Maximum trailer weight is calculated assuming
only the driver is in the tow vehicle and it has all
the required trailering equipment. The weight
of additional optional equipment, passengers and
cargo in the tow vehicle must be subtracted
from the maximum trailer weight.
The following charts show how much your trailer
can weigh, based upon your vehicle model
and options.
2WD Extended Cab Axle Ratio Maximum Trailer Weight GCWR*
Automatic Transmission,
2.9 L Engine 3.73 3,100 lbs (1 406 kg) 7,000 lbs (3 175 kg)
Manual Transmission,
2.9L Engine 3.73 2,100 lbs (952 kg) 6,000 lbs (2 721 kg)
4WD Crew Cab Axle Ratio Maximum Trailer Weight GCWR*
Automatic Transmission,
3.7L Engine 3.73 4,000 lbs (1 814 kg) 9,000 lbs (4 082 kg)
*The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded
vehicle and trailer including any passengers, cargo, equipment and conversions. The GCWR for your
vehicle should not be exceeded.

There are seperate "trailer" fuses in the fuse box in the engine compartment. Separate fuses for trailer left, right and running lights.

Check all fuses, I had the same issue before.

Good luck.

Does the oil light flicker only when the engine is 'idling'? Or does it flicker ALL the time? Does it flicker when the engine is cold? Or, only after the engine warms up? Cause could be low oil pressure (check oil level & condition- should be full and clean), could be the oil pressure sending unit going bad, could be electrical (short) in the oil pressure sending unit wire harness, could be sludge buildup in the crankcase clogging the oil pickup tube to the oil pump, or it could be a clogged oil filter or the oil pump is going bad. If you have an after-market oil filter installed, they somtimes rob the system of pressure. There is a Technical Service Bulletin on this for Hyundai Vehicles. You should use the genuine Hyundai Oil filter.
Does the Check Engine light come ON when this happens? Whenever the "Check Engine" light comes on, there is always a DTC (Diagnostic Trouble Code) stored in the ECM (Engine Control Module). You'll need an OBDII (On-Board-Diagnostics) scanner to retrieve any codes recorded/set in ECM. Once you do this and let us know what, if any codes are set, then we can go from there. OR, take/tow the vehicle into a Hyundai Service Center (dealership), pay the diagnostic fee. They will tell you EXACTLY what the problem is and what's needed to fix it (parts, labor, tax, time-frame, etc.). You could also go to http://www.hmaservice.com/ and register (vehicle by VIN). Afterward, you'll have access to technical information (manuals, wiring diagrams, service bulletins, etc) about your vehicle.