Help Finding Fuse

[8thDegree]

I was wondering if anyone could help me locate a fuse that I have been looking for. The fuse should send power to the light that is supposed to illuminate on the generator slide out switch in the front drivers side electrical bay when the generator bay door is open. It also sends power to the "Gen Out" display on the dash.

Have spent the last month trying to figure out why my dash light does not work (yep, I drove with the generator slide out). In the attached electrical drawing it is marked as 1 amp. Have searched the entire fuse electrical bay and can only find two fuses that are 1 amp. One is listed as "Fuel" and the other is listed as "Security System". One of them is blown, but I have swapped them out trying to get these lights to work, but nothing seems to work.

My friend cry42 has the same coach and he has been trying to help me, but we are still trying to find this fuse. If anyone knows where to look, please share!!!

Warren

[K7JV]

That's odd. It suggests it is on the chassis fuse block in the front run box and labeled "GEN OUT". Are the labels not good on your fuse blocks? If they aren't, and you are looking based on the fuse ratings, you could run the generator out a bit and do some testing. With the key "ON", you could take a voltmeter and go down the fuse block touching the two tiny holes in the top of the fuses with the two leads. If you come to a fuse that indicates a voltage across those two points, that fuse has "blown".

[8thDegree]

Jim,

That was done early on as the drawings on the side wall do not have Gen Out listed. All fuses are good except for a 1 amp fuse that I spoke about in my original post. Got lots of spare fuses collected over the years, but no 1 amp fuse. Did exchange it with a working one and still got no lights showing for Gen Out. I am pretty sure my coach has no "Security System" so that one is now blank.

We are still stumped!!

Got any more ideas/suggestions? Willing to try anything...

Warren

[K7JV]

Hmm. Just a thought. Were you able to check out the functioning of the micro switch in the lower right corner of the drawing? If that's not working the dash light would not operate, as it closes and completes the circuit when the generator is out from its home position.

[8thDegree]

Jim,

Yes, we know that the switch is working. My friend cry42 gave me a new one and I installed it and know it to be working as the white wire coming to it has 12 volts when the switch is in the open position. When you close the switch (like when generator door shuts) there is no ground contact and no 12 volts.

This is what is so confusing, we have power to that wire, but still no lights come on. Besides the dash "Gen Out" light, on my friends coach his gen slide switch lights up when the generator door opens. Here is a picture of his:


Thanks for taking the time to get back with me. Any other ideas or suggestions?

Warren

[K7JV]

When you say the white wire comineg to the switch has 12 volts on it when the switch is in the open position, I would expect that, but I'm unsure of whether you are talking about the switch your friend gave to you, or the microswitch at the back of the generator bay that is operated when the slide is retracted. That microswitch should be a normally closed switch. When the generator is extended, it would go to its normal closed position and provide the ground to complete the path for both the light on the rocker switch and the light on your dash. When the generator is retracted and it pushes on that microswitch the circuit opens and both lights go out.

I'm not sure whether you said that you checked the operation of that switch or the rocker switch. My expectation based upon everything you've told me is that the microswitch is suspect. That is in a bit of a lousy environment and would be prone to failure after many years of seeing the elements and road time.

That switch looks like it might just have one white wire connected to it, and the ground may even be from the body of the switch hosing, if it doesn't have a little pigtail with a connector on it tied to the chassis. You should see +12 V (assuming the key is) on that white wire when you do not push on that switch and you should see 0 V when you do press on that switch.

Keep us posted, and BE WELL AND STAY WELL!

[8thDegree]

Jim,

Sorry to be in a rush late last night, but I was referring to the "micro switch". That is the one he gave me (I think he ordered one and got two) and I did replace it. It does have a white wire that connects using a female spade type connector and another wire which has a circular adapter and the micro switch goes thru and into the body of the front of the coach. That new generator door micro switch is working perfectly as you describe in your last message, I just don't have the Gen Out light come on the dash.

When I looked at the old one, it looked horrible. Was slightly bent, spring had hardly any tension and would only move about 1/2 and inch. New one is much, much better. After replacing, I was shocked to find out that did not make the dash lights come on.

Thus my search has begun for the solution to my problem. My next thought was the bulb in the dash, but once i found out that the gen slide switch in the front electrical bay is supposed to also light up and mine doesn't, now I am wondering where it is supposed to get it's power from. I figure the two lights must be related (connected). Thus looking for the fuse.

What confuses me is that power is going to the back of the micro switch. If there is power there, why does neither light come on???

Thanks again for all your help and I hope that was better in describing the problem. Still open to any suggestions you might have to try.

Warren

[K7JV]

Wow, Warren, I wish I were there to help. I really only see five locations where this circuit is present. One is the illusive fuse. Two is the rocker switch in the front run box to put the slide out and in. Three is the microswitch. Four is the connector between the fuse and the instrument panel and between the instrument panel and the microswitch. And five is the lamp on the instrument panel.

I am not expecting it to be very easy to get to that connector going to and from the instrument panel, and it's not easy to get to the lamp in the instrument display. But if we can find out where the failure point is on the circuit that illuminates the light on the rocker switch, we'll likely be getting closer to finding the root of the problem or problems.

If you can get to it to do it, can you read the voltage to ground on the RED/WHT wire at the rocker switch and the voltage to ground on the WHT wire at the rocker switch. And can you do that first with the generator slide out and then with the generator slide in. You will probably have a good ground lug in the front run box to make that fairly easy.

Let's start with that, and then I'll look at the schematic again to see where to look next.

We're going to get this solved, yet.

[8thDegree]

Jim,

Just to make sure I understand: You want me to take the Red and White wires off the front run box Gen slide out switch and test them for voltage?

I have already tested the white wire on the rocker switch in the Gen slide and it has 12 volts. Do you want to know the exact voltage (like 12.2 volts) or just that it has 12+ volts? If so, I can get you exact numbers.

Thanks again for the help. I will make sure and test those wires this coming Sunday and let you know what I find, so stay tuned.

Warren

[K7JV]

Good morning, Warren. You know what? So far this thread just has you and I in it. If you would like to "message" me your email, we could revert to that. It's a bit easier to move files, or pictures, or whatever, back and forth if we want to do that.

Ok, if you have 12 volts on the white wire at the micro-switch you have actually verified that the fuse (wherever it is) is good, and that there is continuity thru the lamp bulb on the rocker switch so at least one of the two bulbs (speedometer unit or the rocker switch) is still good. That actually tells us a lot.

In order to have 12 volts on the micro-switch, though, it has to be open or the connection from it to ground has to be in trouble. You should be able to push and release the micro-switch and the voltage on the white wire (with it connected) should change from 12 volts to zero volts and back to 12 volts as you press it and then release it.

Think of it this way. If the circuit has 12 volts supplying it, that voltage has to appear somewhere in the circuit. It will appear at the high impedance (resistance) point in the circuit. When the microswitch is pushed open (generator slide closed), that microswitch will be the high impedance device and the 12 volts will appear on the white wire there. When the switch is closed (generator slide opened from its home position), the high impedance device will be the resistive elements in the lamps, and the 12 volts will appear on the source side there. You will see 12 volts on the source side of the lamps and essentially zero volts on the ground side of the lamps.

If you are removing the white wire to test for the 12 volts, then I would ask if you can touch it with your meter to see what the voltage is with it connected to the microswitch and see if it changes when you press and release the microswitch.

Warren, if your coach is wired like the wiring diagram you posted, and if you have 12 volts at the white wire at the microswitch, and neither of the lights are illuminating when the slide is out, about the only thing left is the ground connection for the microswitch. This really is a very simple circuit and we are going to get it working.

Good morning and a Happy May Day, from SW Idaho.

[8thDegree]

Jim,

I sent you the private message so be on the look out for it!

Warren

[K7JV]

Wow, Warren. I don't get it. I sent you an email at 12:12, today, right after lunch. My email is K7JV@ARRL.NET, if you want to try it. I actually clicked on the email link that you sent, so it should have worked.

Anyway, here is what I sent in that email:

Good afternoon, Warren

Again, I wish I were nearer to your location so I could help, better. But based on what you’ve told me, I am really suspecting the ground source for the microswitch, now. The complete path for the electric current should be from the positive terminal of your battery to one side of the fuse in your front run box, then thru the fuse to the load side of the fuse, then to one of the light connection terminals on the rocker switch in your front run box (I think this wire is red and white?), then thru the light filament to the other light connection terminal on the rocker switch, then via the white wire to the microswitch, then from the other side of the microswitch to the ground connection on the frame or other metallic structure, and finally from there back to the negative terminal of the battery, thus completing the circuit.

You have confirmed that the 12 volts is present on the microswitch, so you have really checked out almost all of the circuit and it is good to that point. And you’ve verified that the microswitch is operating correctly, since you replaced the old one with the new one.

Warren, can you verify that the ground wire from the microswitch really is tied well to a good ground connection? Maybe you could take the connection loose scrape the nearby metal where it is attached to make sure you have a clean spot, and then touch the terminal to that spot and see if the light lights. Or, you could test the voltage from the connector on the microswitch that goes to ground and touch your other voltmeter lead to the spot you scraped clean. Or if you have someone that can help you, maybe your leads are long enough that you could hold one voltmeter lead on the ground connection on the microswitch while your help touched the other lead to a known good ground in the front run box.

I really am suspecting that ground connection to be the problem. Hopefully Charles’ drawing will be helpful, as well. Warren, you’re going to get this working, yet. Keep at it.

Thank you for sharing your email. This really is easier than going thru the IRV2 posting process.

Cheers for now and I look forward to hearing how you make out.