The relays are located in an auxillary relay box located under the hood on the drivers side fender near the firewall. If the fuse is blown, replace it, wiggle the wiring on the trailer while someone steps on brakes to check for shorts. The system uses 2 relays. You may have to test the Glowplugs if they get power but do not work. One of the most time consuming tasks with installing an after market car stereo, car radio, car speakers, car subwoofer, car amplifier, mobile amp, mobile navigation or any car audio electronics is identifying the correct color audio wires for a 2003 Ford F250 Truck.
Each Glowplug is like a sparkplug. The Modified Life staff has taken all its Ford car radio wiring diagrams, Ford car audio wiring diagrams, Ford car stereo wiring diagrams, Ford car radio wiring schematics, Ford car wiring diagrams and cataloged them online. The fuse 6 is more likely the problem. One relay turns on for left turn signal, other relay turns on for right signal. One of the problems is you lost the fuel in the lines as soon as the fuelpump was disconnected. You would need to pull them and connect 12 Volts to each. Both relays turn on for brake lamps.
Use a jumper cable and do not touch the threads. . Disconnect one of the Glowpug wires and put in a test light to the wire. Let me know what you find out okay? Diesels need Glowplugs only for starting. Whether your an expert Ford electronics installer or a novice Ford enthusiast with a 2003 Ford F250 Truck, a Ford car stereo wiring diagram can save yourself a lot of time. Posted on Aug 14, 2010 I have an 02 F250 4X4 Super Duty and I belong to a great Ford Message board, these guys are great, give them a try, here's the link which you will have to create a free account. The Timer for the Glowplugs regulates how long the Glowplugs work each cycle.
Use of the wiring information is at your own risk. The Timer box needs feedback from the Glowplugs. You may have taken a wire loose for the Timer or broken a wire. If you would like to help the Modified Life community by adding a car audio wire diagram, car stereo wire diagram or car radio wire diagram to our resource, please feel free to post any additional car audio information about the 2003 Ford F250 Truck on this page. But 1 by 1 you can see a difference in a bad or good glowplug by how each gets hot. Always verify all wires, wire colors and diagrams before applying any information found here to your 2003 Ford F250 Truck. Use power sparingly or you can melt them.
After that, the compression operates the engine. If the Testlight does not light, you are not getting power to the Glowplugs. . . .
. . . . . .
. . . . . . .
. . . . .
. . . . . .