I have a 97 F250 with 7 pin trailer brake plug. I am having problems figuring out a lighting problem and need some direction. The left turn and left brake light on the trailer is not working. Problem is in Truck. There is no power on at the plug for that connection. All the turn signals and brake lights work properly on the truck. Where do I go from here. Looked for obvious but everything looks good. I was getting my camper ready for its first trip when I discovered this problem. Need to know how to get it fixed..is there something I am missing?

 

Check the under hood fuse box, it has a fuse foe each trailer turn light. I'm betting the fuse is blown for the left turn. It should be #7 a 10 amp (red).

 

Don't know which one is #7 so I checked them all. They are all good. I traced the harness with trailer wires all the way up to the front of the truck. goes to a white "don't know what it is?" near the left front tire. the brake lines go into it and divert to different directions. No power in the yellow wire at that point either.

 

On the left side of the fuse box, at the top there is a diode, under that there is an empty space, below that there are 3 maxie fuses. Two 30 amp ones and one 20 amp. Below that last large maxie fuse, the small fuses begin, the first one under the large one is #7. How did you test the fuse, visually or with a test light? Sometimes a bad fuse is hard to see. Also check the clamps that hold the blades of the fuse to make sure they are making good contact with the fuse.

 

Section 18-01: Wiring and Circuit Protection 1996 F-150, F-250, F-350, F-Super Duty Chassis Cab, Motorhome Chassis, and Bronco Workshop Manual

DESCRIPTION AND OPERATION

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Power Distribution Box
Location

F-Series and Bronco vehicles are equipped with a power distribution box located in the engine compartment on the left-hand fender apron.

Content



F-Series Power Distribution Box, Diesel Engine Only






Fuse Position Amps Circuits Protected
1 20 Radio
2 15 Ambulance (Diesel 215 Amp Generator/Voltage Regulator Only)
3 30 Horn Relay, Daytime Running Lamps (DRL), Headlamp Flash-To-Pass
4 25 Trailer Marker Lamps Relay, Trailer Backup Lamps Relay
5 15 Backup Lamps, Daytime Running Lamps (DRL), Trailer Battery Charge Relay
6 10 Trailer Right Stop/Turn Lamps
7 10 Trailer Left Stop/Turn Lamps



Maxi-Fuse Position Amps Circuits Protected
8 30 Injector Driver Module (IDM) Power
9 30 Powertrain Control Module (PCM), PCM Power Relay, Electronic Transmission Control, Injector Pressure Regulator, Injector Driver Module
10 20 See Fuses 15 and 18 (IP Fuse Panel), Starter Relay
11 — Not Used
12 20 Diode Current Flows from Fuse 22 to PCM Power Relay
13 50 See Fuses 5, 9 and 13 (IP Fuse Panel)
14 — Not Used
15 50 See Fuses 1 and 7 (IP Fuse Panel) and Fuse 5
16 — Not Used
17 50 Generator Charge Indicator, Instrument Cluster. See Fuses 2, 3, 6, 11 and 17 (IP Fuse Panel) and Maxi-Fuse 22. Also See Circuit Breaker 12.
18 30 Trailer Battery Charge Relay
19 40 Main Light Switch, Headlamps
20 50 See Fuses 4, 8 and 16 (IP Fuse Panel). Also See Circuit Breaker 12.
21 30 Trailer Electronic Brake Control Unit
22 20 Fuel Line Heater, 215 Amp Generator/Voltage Regulator, PCM Power Relay Coil, Glow Plug Controller
Relay 1 Relay Powertrain Control System
Relay 2 Relay Injector Driver Module (IDM) Relay
Relay 3 Relay Horn
Relay 4 Relay Trailer Tow or Dual Rear Wheel Running Lamps
Relay 5 — Not Used



F-Series Power Distribution Box, Gasoline Engine Vehicles Only






Fuse Position Amps Circuits Protected
1 20 Radio
2 — Not Used
3 30 Horn Relay, Daytime Running Lamps (DRL), Headlamp Flash-to-Pass
4 25 Trailer Marker Lamps, Trailer Backup Lamps Relay
5 15 Heated Oxygen Sensor (HO2S), Backup Lamps, Trailer Battery Charge Relay, Daytime Running Lamps (DRL), Speed Control
6 10 Trailer Right Stop/Turn Lamps
7 10 Trailer Left Stop/Turn Lamps



Maxi-Fuse Position Amps Circuits Protected
8 — Not Used
9 30 PCM Power Relay, Powertrain Control Module (PCM)
10 20 See Fuses 15 and 18 (IP Fuse Panel), Starter Relay
11 — Not Used
12 Diode 20 Diode Current Flows from Fuse 22 to PCM Power Relay
13 50 See Fuses 5, 9, and 13 (IP Fuse Panel)
14 — Not Used
15 50 See Fuses 1 and 7 (IP Fuse Panel) and Fuse 5 (Power Distribution Box)
16 20 Fuel Pump Relay
17 50 Generator Charge Indicator, Instrument Cluster, See Fuses 2, 6, 11, 17 (IP Fuse Panel) and Maxi-Fuse 2. Also See Circuit Breaker 14.
18 30 Trailer Battery Charge Relay
19 40 Main Light Switch, Headlamps
20 50 See Fuses 4, 8 and 16 (IP Fuse Panel). Also See Circuit Breaker 12.
21 30 Trailer Electronic Brake Control Unit
22 20 Ignition System, PCM Power Relay Coil
Relay 1 Relay PCM Power Relay
Relay 2 Relay Fuel Pump Relay
Relay 3 Relay Horn Relay
Relay 4 Relay Trailer Marker Lamps Relay
Relay 5 Relay WOT Relay (4.9 California Only)



Bronco Power Distribution Box






Fuse Position Amps Circuits Protected
1 20 Radio
2 30 4WABS Relay No. 1
3 30 Horn Relay, Daytime Running Lamps (DRL), Multi-Function Switch, Speed Control
4 25 Trailer Marker Lamps Relay, Trailer Backup Lamps Relay
5 15 Heated Oxygen Sensor (HO2S), Backup Lamps, 4WABS, Trailer Battery Charge Relay, Daytime Running Lamps (DRL), Speed Control
6 10 Trailer Right Stop/Turn Lamps
7 10 Trailer Left Stop/Turn Lamps



Maxi-Fuse Position Amps Circuits Protected
8 30 4 WABS Relay No. 2
9 30 PCM Power Relay, Powertrain Control Module (PCM)
10 20 See Fuse 18 (IP Fuse Panel), Starter Relay
11 — Not Used
12 (Diode) 20 Ignition System, PCM Power Relay Coil
13 50 See Fuses 5, 9 and 13 (IP Fuse Panel)
14 30 Rear Window Defrost
15 50 See Fuses 1 and 7 (IP Fuse Panel) and Fuse 5
16 20 Fuel Pump Relay
17 50 See Fuses 2, 6, 11 and 17, Maxi-Fuse 22 and Circuit Breaker 14
18 30 Trailer Battery Charge Relay
19 40 Main Light Switch, Headlamps
20 50 See Fuses 4, 8 and 16 (IP Fuse Panel). Also See Circuit Breaker 12.
21 30 Trailer Electronic Brake Control Unit
22 20 Diode Current Flows from Fuse 22 to PCM Power Relay
Relay 1 Relay PCM Power Relay
Relay 2 Relay Fuel Pump Relay
Relay 3 Relay Horn Relay
Relay 4 Relay Trailer Marker Lamps Relay
Relay 5 Relay 4WABS Relay No. 2



F-Super Duty Motorhome Power Distribution Box






Fuse Position Amps Circuits Protected
1 15 Cigar Lighter
2 20 Headlamp Flash-to-Pass, Daytime Running Lamps (DRL) Module
3 20 Horn Relay, Speed Control
4 20 Body Builders Battery Accessory Feed
5 15 Heated Oxygen Sensor (HO2S), Backup Lamps, Blower Motor Relay
6 10 Speed Control (Main Power to Module)
7 — Not Used
8 — Not Used



Maxi-Fuse Position Amps Circuits Protected
9 — Not Used
10 — Not Used
11 20 Transmission Range Sensor, Starter Motor Relay, Ignition Control Module
12 Diode PCM Relay
13 30 PCM Relay, Fuel Pump Relay, E4OD Transmission, Engine Controls
14 60 Ignition Switch
15 — Not Used
16 50 Blower Motor Relay
17 60 Headlamps, Main Light Switch, PSOM, Exterior Lamps, Interior Lamps
18 20 Fuel Pump Relay, Fuel Sender
19 — Not Used
20 — Not Used
21 — Not Used
22 20 Ignition Control Module, Ignition Coil, Distributor, Radio Capacitor, PCM Relay Coil
Relay 1 Relay PCM Power Relay
Relay 2 Relay Fuel Pump Relay
Relay 3 Relay Horn Relay
Relay 4 Relay Blower Motor Relay
Relay 5 — Not Used


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You've said that you're not getting signal at the left turn signal/brake lamp pin on the trailer connector. Have you tested the wire feeding that pin behind or downstream from the connector? It should be a yellow wire.

If the fuse for that circuit is not blown but you're not getting signal on that pin at the connector, either the connector is bad or there's a break in that circuit between the fuse block and the connector. If you get power on the yellow wire behind the trailer connector, you can simply replace the connector with # 118242 if you have the F250LD or # 20023 for the F250HD.

If you don't have power on the yellow wire behind the connector, I'd simply cut the yellow wire a foot rearward of the trailer connector, add a length of wire long enough to reach the wiring harness feeding the left turn signal on the truck and tap into that circuit. This will be easier than trying to trace the left turn circuit all the way to the fuse box looking for a broken wire or loose connection.

If you use the link below, you can look at some articles that will help walk you through the troubleshooting process.

https://www.etrailer.com/expert-67.html

 

That is exactly what I did to make a temp fix until I return from a trip. Then I want it working like it is suppose to. Thank you.

 

Thank you ever so much. I will look into this very close ..doctors apts today. Will check it out tomorrow.