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dp7 · 01-12-2021, 01:05 PM

I needed a 12v switched & unswitched line for installation of a dash cam. Both were available at the KIB fuse panel in the first bay on the driver side. This is simply a fuse panel for I do not have the KIB multiplexing system found on some other coaches. Photo & drawing attached.

The fuse taps need to be oriented so the new tap line plugs into the battery side, not the load load side of the existing fuse slot. Easy enough to check with a volt meter after removing the existing fuse. Unlike a car I found voltage on both the battery side & the load side of the existing fuse slot. This was quite strange, for in a car fuse box there is voltage on the battery side & not the load side when a fuse is removed.

I noticed that each fuse on the KIB panel has an LED adjacent to it. At first I thought that the LEDs were to identify a blown fuse by lighting up. However they did not light when the fuse was removed. Perhaps the LED has something to do with the voltage being on both sides of the fuse slot.

Once the fuse taps were inserted into the existing fuse slot the Kwikee step retracted even though the taps were not installed in the step fuse position.

Anyone have insight into what the LEDs on the KIB fuse panel are for & why there is voltage on both sides of the existing fuse slots when the existing fuse is removed?

Skip426 · 01-12-2021, 05:38 PM

The voltage reading is a result of the led circuitry, too light up when fuse is blown .

The mili amp voltage will give a read out on a volt meter . Use a 12 volt test light to identify the power side of the fuse.

As for the step operation , Kwikee system has three fuses involved in step operation , I'll see if I can blow up the diagram to figure anything out for that part of your problem.

dp7 · 01-13-2021, 01:23 AM

Quote:

Originally Posted by Skip426

The voltage reading is a result of the led circuitry, too light up when fuse is blown .

The mili amp voltage will give a read out on a volt meter . Use a 12 volt test light to identify the power side of the fuse.

As for the step operation , Kwikee system has three fuses involved in step operation , I'll see if I can blow up the diagram to figure anything out for that part of your problem.

Thanks. I spent some quality time on it today & think I now have it figured out.

Skip426 · 01-13-2021, 11:41 AM

Quote:

Originally Posted by dp7

Thanks. I spent some quality time on it today & think I now have it figured out.

Should the issue with the steps continue , I'd say that replacing the fuse taps with inline fuses and connecting directly to the power studs is in order , completely getting clear of the LED circuitry.

dp7 · 01-14-2021, 01:41 AM

Quote:

Originally Posted by Skip426

The voltage reading is a result of the led circuitry, too light up when fuse is blown .

The mili amp voltage will give a read out on a volt meter . Use a 12 volt test light to identify the power side of the fuse.

Thanks Skip. Surprised that the voltage drop across the fuse slot (fuse removed) is only about 1 1/2 volts less than battery voltage. The LED bypass must be pretty low resistance, which seems that it would still allow a significant amount of current thru with a blown fuse.

dp7 · 01-14-2021, 02:05 AM

Quote:

Originally Posted by Skip426

Should the issue with the steps continue , I'd say that replacing the fuse taps with inline fuses and connecting directly to the power studs is in order , completely getting clear of the LED circuitry.

The cause of the step retraction turned out to be rather strange. The tap connected to the red wire is for constant power to the dash cam power supply box. The tap for the yellow wire goes to the same power supply box to supply switched power. The last wire to the power supply box is ground.

What I discovered was that the voltage from the red tap (constant power) was backfeeding to the yellow tap thru the dash cam power supply box. This put voltage on the KIB ign fuse bus even though the ign switch was off. The step fuse detected the errant voltage on the fuse board & thought the ign switch was on & retracted the step.

The backfeeding thru the dash cam power supply box stopped once the ground wire was attached. Seems like a simple diode in the dash cam power supply box could have prevented the backfeeding. I am now reluctant to use the dash cam power supply box in case the ground connection fails in the future.

Unfortunately, there is not enough nut engagement on the power studs to add more lugs. And it would not mitigate the potential floating ground backfeed issue.

Skip426 · 01-14-2021, 11:48 AM

Quote:

Originally Posted by dp7

Thanks Skip. Surprised that the voltage drop across the fuse slot (fuse removed) is only about 1 1/2 volts less than battery voltage. The LED bypass must be pretty low resistance, which seems that it would still allow a significant amount of current thru with a blown fuse.

Reduced voltage, through a circuit is one thing , reduced amperage is another.

Case in point ; from my HWH levelers ; the fuse in the photo , is not blown control panel LEDs lit up but nothing would function , voltmeter showed good volts to the control pad , 12 volt bulb test light barely glowed.
Back to your question about the LED on the board not lighting up with the fuse out ; I don't have these LEDs on my vintage board , so I'm not sure ; but it would seem to me that there would have to be a load applied to the circuit for the LED to light up with the fuse out; any light needs a ground path.

ptw · 01-14-2021, 05:23 PM

I was having trouble with my 12 volt outlet blowing fuses intermittently until I finally replaced the outlet. What I found while I was having trouble is that if I had a load plugged into the outlet the LED would light indicating the blown fuse. If there was nothing plugged into the outlet, the LED does not light. The LED is parallel with the fuse and it needs a load to complete the circuit. You can easily demonstrate this by pulling the fuse for the dash power outlet with a load plugged into the outlet, observe the light, then remove the load and the LED light will go out.

This is the same case for the fuse on the summer loop pump. Be sure the summer loop pump is not running and pull the fuse. The light will not go on. Run the hot water faucet in the coach for a few minutes and the LED blown fuse light will come on when the power for the summer loop pump comes on.

Also it was mentioned about current passing through the LED. Only milliamps will flow through the LED light.