PDC blowing fuses????

[SteelHeadz]

s
That's a great idea. Measuring resistance on the circuit
will give you an idea where the short is. The only
obstacle is that it's intermittent. You would have to be patient in isolating the culprit. I'll start with this schematic diagram where the circuits run from the PDC , fuse block, relay , fuel pump and PCM.

Looking at this second diagram for the splices, it seems that checking the relevant circuits where the closest to the PDC may also be a possible culprit. As i previously suggested, check the wirings on the O2 sensor, and all the other one's spliced into this circuits.

 

[captjanes]

yes i used the ohm meter to test for resistance. and i tracked the wiring diagram. i already had a wiring diagram from a haynes manual i got for my jeep it is the same wiring diagram. i also used a amp meter to see if a wire is drawing more juice then another to cause a ground but they all fine.. that is why i am thinking my relay is breaking down when it gets hot.

 

[SteelHeadz]

Is the fuse still blowing?

 

[captjanes]

yes it is still blowing i think i got the problem found now.. i tested the resistance in my fuel pump relay to the resistance of a new relay and it seems mine is weak so that means it must open and break down when it is hot.. i am almost for sure this is the problem

 

[SteelHeadz]

That would be weird. If the circuit opens it should not blow a fuse since there's no continuity. I would suspect that if it was a relay problem, it would be a short to ground or a short to voltage issue. A constant spike on the voltage can blow a fuse and that would be a possible scenario but rarely encountered. The dark green and black from the PDC and the dark green and white from the relay is the circuit i would concentrate on diagnosing for an intermittent short to ground or short to voltage. IF it's possible for you to disconnect the fuel level sensor wire, i would try that just to see if the problem is in that circuit for a short in the fuel level sensor. That circuit is otherwise known as a pullup driver with a resistor.

 

[bootguy]

To double check the wiring diagram, go to the dealership and have them pull your build sheet and print your wiring diagrams for your vehicle. I did this for my sons jeep and found minor differences from the haynes manual. If nothing else you will find out what specific things that fuse goes to.