My 2002 f350 diesel recently started acting up, the first sign was when my park brake light came on and the chime came on. I mucked around with a few things but still wont go away, while i was doing this a buddy noticed i had no brake lights at all and under further inspection no signals either, not even the clicking noise you usualy hear also the cruise controll has stopped working aswell as the little screen mounted to the roof near the rear view mirror. I am fairly clueless with electrics (i dont even own a multi meter) but i do want to figure this out, i have noticed that fuse 20 was burnt and after replacing it it pops pretty much right when i push my foot on the breaks or signal. And help is appreciated
Thanks Ryan

 

One thing you havent mentioned is if you have installed any new lighting or if you wired anything new ( stereo or brake controller etc ) in or added something in? If you have that could be something that is contributing to it.

If you have plug ins for a trailer, just go back there and make sure that everything is okay and nothing that would be making a short, then crawl under the back and make sure that wiring where the trailer connections plug in are connected well and that the wiring looks okay and nothing is shorting out on the frame.

If your fuse is popping like that you could have a short somewhere that is causing it. I believe there is a pressure switch at the brake pedal that when you push on the brake that it activates check and make sure that is good along with the wires to it.

I would check to make sure that switch is still good and the wiring is okay. Next thing to do would be to check and see if you have any other fuses blown
Once you have looked to see that you have no more blown Fuses , I would then check the relays in the fuse box under the hood and make sure they are good and working.

If you have added nothing new electronics wise and your wiring looks good and nothing is grounding out, my bet is that a relay went kaput.

 

Okay so the truck does have aftermarket trailer brake controller as well as an aftermarket trailer plug in the box. I've followed the wires from the back of the truck forward and did notice one spot on the harness for the trailer plug that had rubbed through so i taped it up thinking i had it beat but it still pops fuses. Im also blowing fuse #12 for the cigar lighter, any idea what relay i would be looking for?

 

If you have an owners manual for the truck some where in the book there should be a layout for the fuse panel.


Hopefully this will help, it's divided into two parts one for the fuse box inside the truck, the other is for the power distribution box * fancy name for the ones under the hood...lol

Inside truck fuse panel:

Interior Fuse Panel

Click the image to open in full size.

Fuse/Relay
Location
Fuse Amp
Rating
Passenger Compartment
Fuse Panel Description
1 20A Turn/Hazard Lamps
2 10A Airbag Module
3 20A Cigar Lighter, Data Link Connector
4 10A Glove Box Lamp, Map Lamps, Power
Mirrors, Underhood Lamp
5 — Not Used
6 — Not Used
7 5A Power Window/Lock Switch Illumination
8 5A Radio, Headlamp Switch Illumination
9 — Not Used
10 15A Dual Fuel Tanks
11 30A Wiper Motor, Wiper Run/Park Relay Coil,
Wiper Hi/LO Relay Coil, Washer Pump
Relay Coil
12 15A Horn
13 20A Stop Lamps, Center High-mount Stop
Lamp, Trailer Tow Stop Lamp, Speed
Control
14 10A Dome Lamp, Cargo Lamp, Courtesy Lamps,
Running Board Lamps
15 5A Stop Lamp Switch (Logic): Generic
Electronic Module (GEM), Powertrain
Control Module (PCM), Four Wheel
Anti-lock Brake System (4WABS) Module,
Brake Shift Interlock, Cluster and PCM
Keep Alive Memory
16 15A Instrument Cluster, Hi-beam Headlamps
17 — Not Used
18 — Not Used
150
Fuse/Relay
Location
Fuse Amp
Rating
Passenger Compartment
Fuse Panel Description
19 10A Auxiliary Powertrain Control Module
(APCM) (Diesel only), Instrument Cluster,
GEM Module, Overdrive Cancel Switch, Idle
Validation Switch (Diesel only), Overhead
Console, Diesel PCM via Clutch
20 15A Starter Motor Relay Coil, Clutch Switch
21 — Not Used
22 10A Air Bag Module, Passenger Air Bag
Activation/Deactivation Switch, Blower
Motor Relay Coil
23 — Not Used
24 10A A/C Clutch, Blend Door Actuator, Trailer
Tow Battery Charge Relay Coil, Four Wheel
Anti-Lock Brake System (4WABS), Turn
Signal
25 — Not Used
26 — Not Used
27 10A Ignition Run Power Feed (Customer Access)
28 10A Brake Shift Interlock, DRL Relay Coil,
Speed Control Module, Backup Lamps,
Trailer Tow Backup Lamp Relay Coil,
Electronic Shift On The Fly Hub Lock
Solenoid, Vacuum Pump Motor
29 5A Instrument Cluster (Charge and Airbag
Warning Lamps)
30 30A PCM Relay Coil, Ignition Coil (Gasoline
only), Fuel Heater (Diesel only), Wastegate
Solenoid (Diesel only), Injector Driver
Module Relay Coil (Diesel only)
31 — Not Used
Relay 1 — Interior Lamp Relay
Relay 2 — Not Used
Relay 3 — Horn
Relay 4 — Power Window One Touch Down Relay
Relay 5 — Accessory Delay Relay

---------------------------------------------------------------------


Under hood power distribution box

Fuse/Relay
Location
Fuse Amp
Rating
Power Distribution Box Description
1 7.5A * Trailer Tow Left Stop/Turn Lamp
2 10A* Washer Pump
3 7.5A* Trailer Tow Right Stop/Turn Lamp
4 20A* Trailer Tow Backup Lamps, Trailer Tow
Park Lamps
5 20A* (Gasoline
only)
5A* (Diesel only)
Gasoline only-PCM, Fuel Pump Relay Coil,
Mass Air Flow Sensor, Fuel Injectors
Diesel only-Dual Alternator A Field
6 10A* Gasoline only-A/C (CASS)
Diesel only-Single or Dual Alternator
A Field, Regulator
7 20A* (Gasoline
only)
5A* (Diesel only)
Gasoline only-Vapor Management Valve,
HEGO Sensors, Intake Manifold
Communication Control, EVR Solenoid,
PCM, Canister Vent Solenoid
Diesel only-Dual Alternator A Field
8 15A* Trailer Tow Electronic Brake
Illumination, Park Lamps, Trailer Tow
Park Lamp Relay Coil
9 10A* Left Headlamp (Low Beam)
10 20A* Power Point
11 10A* Right Headlamp (Low Beam)
12 15A* Daytime Running Lamps (DRL)
Resistor
13 30A** Multi-function Switch, Headlamps
14 60A** Anti-Lock Brake System
15 — Not Used
16 30A** Trailer Tow Battery Charge
17 30A** Electronic Shift On The Fly Relay,
Transfer Case Shift Motor
18 30A** Power Seat
19 20A** Fuel Pump Motor, PCM
20 50A** Ignition Switch (B4 & B5)
153
Fuse/Relay
Location
Fuse Amp
Rating
Power Distribution Box Description
21 50A** Ignition Switch (B1 & B3)
22 50A** Junction Box Battery Feed
23 40A** Blower Motor
24 30A**
(Gasoline only)
20A**
(Diesel only)
PCM Power
25 30A*** Power Windows
26 20A** If equipped with Remote Keyless
Entry-Driver Door Unlock Relay Coil,
All Door Unlock Relay Coil, All Door
Lock Relay Coil, Park Lamp Flash
Relay, If not equipped with Remote
Keyless Entry-Power Door Lock Motors
27 - (Gasoline only)
30A**
(Diesel only)
Gasoline only-Not Used
Diesel only-Injector Driver Module
28 30A** Trailer Tow Electronic Brake Controller
29 20A** Radio
30 -- PCM Power Relay
31 -- Blower Motor Relay
32 -- A/C CASS (Gasoline only), Injector Driver
Module Power Relay (Diesel only)
33 -- Washer Pump Relay
34 -- Windshield Wiper Park/Run Relay
35 -- Windshield Wiper HI/LO Relay
36 -- A/C Clutch Diode
37 -- PCM Diode
38 -- Trailer Tow Backup Lamp Relay
39 -- Trailer Tow Battery Charge Relay
40 -- Electronic Shift On The Fly Relay #1
41 — Electronic Shift On The Fly Relay #2
__________________

That should help so you can check and see if all is well under there, but check to make sure the fuses are good and the relays.

 

BTW check the wiring from the brake controller and make sure that is all good at the connection points. I gather you have had it in a for a while, but I would check the wiring there to make sure nothing is shorting out, better to check it then not.

 

Update:

Found my in box trailer plug had been pinched when we installed a headrack yeaterday causing my short. I pulled the whole plug out and cut all the wires from it off right at the main harness, i have my brake lights back and my hazzards work but still no turn signal and my ebrake still thinks its on. Its strange i still have some issues because they all came at once so i figured they would all be realated. Im a little stumped with these signals because the hazards work perfect all 4 corners and there is a solid click from under the dash just nothing when i use the signal swicth

 

-Well that is some progress, I am going to guess that you will need to check the fuses and relays, when that short happened it may have blown a fuse or relay and that I would presume is why you only have a few things working.

I would go thru fuses one by one and then check the relays, my bet is that there is still a fuse or relay issue causing you to not have everything working as it should. There should be a fuse or a flasher type fuse that could have partially blown and hence no signals... worth a look

Good job on finding the short.One problem down, find the other and you should be back in good shape

 

So ive checked all the fuses and ive only found the two out both have been replaces and niether have pop'ed again but im not sure if thats all the fuses. Is there any in the engine bay? I saw the 3 little boxed but they all seem to be relays in there, also how do you check a relay? Should i just send power to the low power side and check the main power side for continuity?

 

You can give Eric The Car Guy's video a look , he shows how to test and check relays.... and probably does a better job explaining it then me... You can find a electric multi meter fairly cheap and that should help be a cheap way to test them, rather than just running out and buying a bunch of new relays.



This is another of Eric The Car Guy's videos on basic electrical trouble shooting that may help

 

No luck. All relays tested fine, pulled all the fuses and no a single one was burnt and im still at the same place as before. If it wasnt for the dinging at every start stop i could probably live with no signal lights for a bit but this chime is driving me nuts! Im kinda at a loss, i want to test the signal switch because the lights on the cluster dont even light but the ebrake light and chime have nothing to do with that switch

 

No worries I dont know if you have done this yet , but make sure that you have checked all the fuses under the dash and under the hood. There are fuses under the hood and the dash that both are fused for the lights


If you have done that then it's time to check your flasher unit ( it is almost like the ones you'd see in the old days but slightly different ) The Hazards will work, but turn signals usually wont if that little unit is toast.

You can try to test this but it's a pain in the you know what just due to where it is, If you were going to test it you'd have to go there anyways so I suggest you replace it.

The flasher unit I think has gone kaput. So your going to have to take off the panel covering where the fuse box is of ....then you are going to remove the screws holding the heater duct work you will see there when you look at it....once the heater duct in that area is removed you ought to be able to get to the the flasher box cover.... your going to have to reach up under the dash and then take the cover off of the box.... once you have it off then remove the flasher and replace it with a new one.

Before you put it all back together check to see if your turn signals are back. I will keep my fingers crossed for you