First things first, I confirmed the customer's concern. The AC and the wipers were inoperable. Next thing to do was to pull up a wiring diagram and start checking the circuit.
I first checked out the two fuses in the fuse block on the left-hand side of the dash. The wiper and AC fuse are next to one another. At first, I wondered if something might be going on with the terminals. When I checked the fuses (Fuse 11 Wiper 25A and Fuse 12 HTR-AC 25A) with KOEO (Key On Engine Off) and the AC and wipers in the on position, I got ground. No power was coming to the fuses.
Now that I knew there was no power to these two fuses, it was time to find out what their power source was. Again, consulting the wiring diagram, I saw power was supplied to these circuits by the IGN B 50A fuse. I saw the radio was also powered on this circuit, and when I checked the radio, as expected, it did not work either. The IGN B 50A fuse is located in the Power Distribution Box under the hood, on the left (driver's) side of the engine compartment.
The fuse I'm pointing out is the IGN B fuse. When I checked it with the Power Probe it showed one side with power and the other side without. This meant we had a blown (melted) fuse. I replaced the fuse, turned the key to KOEO and tried the problem circuits. They all now worked.
Of course, fuses don't just blow for the fun of it. When I reported my findings to the customer, telling him we would need to do further diagnostics to determine the cause of the blown fuse, he opted to pick it up and run it until he has any more trouble out of it.
I advised him on the potential problems and inconveniences that could result from this; but, he decided to pick the truck up as is anyway.
I just hope it doesn't decide to blow when it's raining!
No comments:
Post a Comment