dcrbtt
Well-known member
Is there an in place fuse tester.
My water pump quit working and there are so many different non labeled fuses in my rig.
My water pump quit working and there are so many different non labeled fuses in my rig.
Fuse Tester
- Thread starter dcrbtt
- Start date
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DonTom
Well-known member
HueyPilotVN
Well-known member
You can also use a simple 12 volt test light.
Clip the wire to ground and touch the point to each of the two indentation on the fuse one at a time.
If both light up the fuse is OK.
If only one lights up the fuse is blown.
Clip the wire to ground and touch the point to each of the two indentation on the fuse one at a time.
If both light up the fuse is OK.
If only one lights up the fuse is blown.
John From Detroit
Well-known member
Get three things.. One is an automotove 12 volt test light and the other things are about 25 or so feet of 18-22 ga and a pair of alligator clips Put one clip on each end of the coil of wire
The auto test light looks like a ice pick with a wire coming out the handle and a light bulb inside
Test procedure.. Hook the clip on the light to either a known good ground or the one end of the etension wire. the other end of the extension goes to a good ground. Touch the tip of the probe to a known good 12 volt source.. bright light.GOOD Dark reseat the lamp and try again.
Blade fuses have a small window in the top each end. Touch tip to each window
BRIGHT-BRIGHT = GOOD FUSE
Dark-Dark = Untested
Bright-Dark or Dark-Bright = Blown fuse
Test a dozen fuses in less than a minute.
The auto test light looks like a ice pick with a wire coming out the handle and a light bulb inside
Test procedure.. Hook the clip on the light to either a known good ground or the one end of the etension wire. the other end of the extension goes to a good ground. Touch the tip of the probe to a known good 12 volt source.. bright light.GOOD Dark reseat the lamp and try again.
Blade fuses have a small window in the top each end. Touch tip to each window
BRIGHT-BRIGHT = GOOD FUSE
Dark-Dark = Untested
Bright-Dark or Dark-Bright = Blown fuse
Test a dozen fuses in less than a minute.
Domo
Well-known member
For troubleshooting I always remove the fuses I want to test. If they are simply prodded with a meter's probe, that will not break any corrosion/oxidization that may be causing an interruption of current flow. i.e., seeing a light light up when touching the exposed ends of the fuse does not mean the terminal clips holding the fuse are conducting. At the least, I will spin a fuse (if round) to help break any corrosion.
Here's my general go-to when troubleshooting in our 16 year-old MH;
"Bring CRC contact cleaner and lubricant, meter, crimpers and dielectric grease with you when troubleshooting. Remove all the related plugs from their sockets, spray both with CRC and then insert+remove about three times to help break any corrosion. Continue, including removing fuses or 12 relays/breakers from sockets and dowsing their contacts and sockets with CRC. While you're doing this, look for crimp-on connections and re-crimp them (or replace if you see green/oxidation of the wire). Trace all ground wires to the ground block or chassis. Remove them, scrape any dirt or paint off, clean the contact and bolts and put it all together."
Here's my general go-to when troubleshooting in our 16 year-old MH;
"Bring CRC contact cleaner and lubricant, meter, crimpers and dielectric grease with you when troubleshooting. Remove all the related plugs from their sockets, spray both with CRC and then insert+remove about three times to help break any corrosion. Continue, including removing fuses or 12 relays/breakers from sockets and dowsing their contacts and sockets with CRC. While you're doing this, look for crimp-on connections and re-crimp them (or replace if you see green/oxidation of the wire). Trace all ground wires to the ground block or chassis. Remove them, scrape any dirt or paint off, clean the contact and bolts and put it all together."
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Kirk
Well-known member
Several of the suggestions will work, most of the time. The only absolutely accurate under all circumstances way is to remove the fuse and check it with an ohm meter. A better way to check the pump is to use the multimeter on the volts DC scale and see if there is 12V at the pump. When your pump is turned on it is controlled by a pressure switch that is physically on the pump so there should be voltage to it whether running or not. Here is a picture of a typical RV fresh water pump.
In this pump the wares connect directly to the pressure switch and no matter where the wires are physically located, that switch is what turns the pump on and off. While most of them are adjustable, if your pump does not run at all now but used to do so, it is pretty safe to assume that the switch adjustment is not the problem.
Gary RV_Wizard
Site Team
It's fairly common for a water pump to have an inline fuse near the pump itself, so check for that too.
DonTom
Well-known member
Lou Schneider
Site Team
- Joined
- Mar 14, 2005
- Posts
- 13,344
This is the best answer. You want to see 12 volts on both sides of a good fuse. A tester that goes directly across the fuse will only show the fuse is blown if there is 12 volts on one side of the fuse and the load side has continuity to ground.
For example, it won't find a blown fuse if the power switch on that circuit has been turned off - when the switch is open it breaks the path to ground on the load side of the fuse.
DonTom
Well-known member
The one I linked to has a battery in it and will light up even if the fuse is out of the circuit.
-Don- Reno, NV
CharlesinGA
Well-known member
If this is a 2019 RV it is new enough it should have blown fuse indicators on the fuse panel. Little LEDs next to each fuse that illuminate when 1) there is power available to the fuse panel and 2) there is a load on the circuit in question. See the attachment at the bottom of this post for an example.
You can also buy fuses with LED indicators built into them. Bussman calls them easy ID type ATC fuses while Littelfuse calls them Smart Glow type ATO fuses (ATO and ATC are the same size/type blade fuse that your RV uses.) Please don't buy the cheap knockoff fuses, as the ability to blow when they should at the proper amperage is flawed and could damage your circuits or components as a result.
If your water pump switch is located in the levels panel, most likely the same fuse that powers the levels panel also powers the pump. Is your levels panel working?
Forest River FR 3 electronic owners manuals
Charles
You can also buy fuses with LED indicators built into them. Bussman calls them easy ID type ATC fuses while Littelfuse calls them Smart Glow type ATO fuses (ATO and ATC are the same size/type blade fuse that your RV uses.) Please don't buy the cheap knockoff fuses, as the ability to blow when they should at the proper amperage is flawed and could damage your circuits or components as a result.
If your water pump switch is located in the levels panel, most likely the same fuse that powers the levels panel also powers the pump. Is your levels panel working?
Forest River FR 3 electronic owners manuals
This is putting the meter circuit into the current carrying circuit, parallel with the fuse, good way to blow the meter. The indicators will not show a blown fuse if as Lou noted in post #10 above, everything in the circuit is turned off and thus no ground in the circuit.
Charles
Attachments
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DonTom
Well-known member
And some RVs come stock with them, such as my 2022 Class A.
Very handy to be able to instantly see a blown fuse.
-Don- Reno, NV
OldWEB
Well-known member
A voltmeter has almost infinite ohms resistance, it is designed to measure voltage, will NOT conduct current. You are confusing using a ammeter on a pure voltage source, no resistance... THAT will go "POP"!
DonTom
Well-known member
OldWEB
Well-known member
Yes you could, but just another toy to carry around, when, like most RVs, you will have a multimeter that has an ammeter built into it. Just knowing how to use it properly and careful you do NOT try to measure voltage while in the 'amps' range/position... Typically need to move the one test lead and then forget to put it back to volts/ohms when required!! I have blown many meter fuses....
Kirk
Well-known member
That is exactly the proper way to check a fuse in a live circuit. With the meter set to a voltage scale that is at least double the highest possible voltage in the circuit and sent either ac or dc depending on what powers the circuit, you then put one probe on one end of the fuse and the other probe on the opposite end. If you measure the source voltage that fuse is open or bad. If you measure 0V then the fuse is good and conducting.
Now if you set your meter on an ohm scale and then measure voltage or amps you will probably blow a fuse in the meter and most modern meters are fused to prevent operator errors. Over the years of making a living using various test equipment, I have destroyed a few meters, the worst was with my boss riding along on a service call and that meter was not fused!
