MIKE BROGDON
OBS Enthusiast
As always, thank you in advance for any and all help and information. My truck is a 1994 K1500. The fuse block clips into the bottom of the dash just above the emergency brake.
The short version: Im getting unwanted power from my courtesy circuit. With the courtesy fuse installed into the fuse block, I am getting 12 Volts to my windshield wiper motor, and to my power windows with the key out of the ignition. When I pull the courtesy fuse out, the unwanted power goes away and the two components work as they normally should. Could this be a bad fuse block? Can I test this by removing the fuse block from the truck and place it on the bench, apply 12 Volts to the courtesy pin, and see if I have volts at the windshield wiper pin and the power window circuit breaker pin?
The more detailed version: Since I have had the truck, Ive had issues with a power drain. With the key out of the ignition I can turn on my windshield wipers and roll the power windows down. I found that by removing the courtesy fuse, everything works normally as it should. When the fuse is installed, I have power to these two componets. I drove the truck for a few years and just left the courtesy fuse out, but I currently have the steering column out of the truck and with the extra room underneath the dash, I wanted to get this little bug marked off of my list of things that need to be fixed.
So far I have chased the courtesy wires from one side of the truck to the other. I have not found any obvious splices or boogered up connectors. I also have not been able to find any areas where the power window circuit or wiper circuit is tapped into the courtesy circuit. With the courtesy fuse installed, I have 12 volts at the pink power window wire coming from the front of the conveince center that is mounted on the inside of the firewall just to the left of the brake pedal that goes directly to the power window switch. With the courtesy fuse removed, the power goes away at the conveience center. This meant that my issue is between this conveience box and battery. According to the power distribtion diagrams the window circuit in a nutshell looks like this:
Battery-----Junction box on passenger side of firewall-------fuse box--------convenience center---------
I pulled the convience center from the firewall, and I did not see my courtesy wire tapped into the pin for the power window on the backside of the box. I also did not see any jumped wires going from one pin to another that would supply power from any other circuit. I then moved back to the fuse box.
(FUSE BOX) With my probe in the power window fuse hole, I am getting 12 volts constant. With the probe still in place, I remove the courtesy fuse and the voltage goes away. The same goes with my windshield wiper fuse hole. I pull the courtesy fuse and the voltage goes away.
I can roll the windows up and down, but obviously with the column out I cant activate the wipers, however I probed the power wire going into the wiper motor and it is the same, 12 volts with the courtesy fuse in, no volts with fuse out.
So, is it likely or possible that the fuse box is malfunctioning, and allowing the courtesy circuit of the fuse block to power other areas of the fuse block when they should not have power?
I greatly appriciate any help in this. This has been a very frusterating issue.
Thanks, Mike.
Ill post some of the diagrams I have been looking at.
The short version: Im getting unwanted power from my courtesy circuit. With the courtesy fuse installed into the fuse block, I am getting 12 Volts to my windshield wiper motor, and to my power windows with the key out of the ignition. When I pull the courtesy fuse out, the unwanted power goes away and the two components work as they normally should. Could this be a bad fuse block? Can I test this by removing the fuse block from the truck and place it on the bench, apply 12 Volts to the courtesy pin, and see if I have volts at the windshield wiper pin and the power window circuit breaker pin?
The more detailed version: Since I have had the truck, Ive had issues with a power drain. With the key out of the ignition I can turn on my windshield wipers and roll the power windows down. I found that by removing the courtesy fuse, everything works normally as it should. When the fuse is installed, I have power to these two componets. I drove the truck for a few years and just left the courtesy fuse out, but I currently have the steering column out of the truck and with the extra room underneath the dash, I wanted to get this little bug marked off of my list of things that need to be fixed.
So far I have chased the courtesy wires from one side of the truck to the other. I have not found any obvious splices or boogered up connectors. I also have not been able to find any areas where the power window circuit or wiper circuit is tapped into the courtesy circuit. With the courtesy fuse installed, I have 12 volts at the pink power window wire coming from the front of the conveince center that is mounted on the inside of the firewall just to the left of the brake pedal that goes directly to the power window switch. With the courtesy fuse removed, the power goes away at the conveience center. This meant that my issue is between this conveience box and battery. According to the power distribtion diagrams the window circuit in a nutshell looks like this:
Battery-----Junction box on passenger side of firewall-------fuse box--------convenience center---------
I pulled the convience center from the firewall, and I did not see my courtesy wire tapped into the pin for the power window on the backside of the box. I also did not see any jumped wires going from one pin to another that would supply power from any other circuit. I then moved back to the fuse box.
(FUSE BOX) With my probe in the power window fuse hole, I am getting 12 volts constant. With the probe still in place, I remove the courtesy fuse and the voltage goes away. The same goes with my windshield wiper fuse hole. I pull the courtesy fuse and the voltage goes away.
I can roll the windows up and down, but obviously with the column out I cant activate the wipers, however I probed the power wire going into the wiper motor and it is the same, 12 volts with the courtesy fuse in, no volts with fuse out.
So, is it likely or possible that the fuse box is malfunctioning, and allowing the courtesy circuit of the fuse block to power other areas of the fuse block when they should not have power?
I greatly appriciate any help in this. This has been a very frusterating issue.
Thanks, Mike.
Ill post some of the diagrams I have been looking at.