ridgeviewroad Report post Posted February 4, 2016 What causes corrosion where the fuse spade enters the fuse holder? This does not occur on every fuse probably less than 10%. The supply side of the fuse holders is reading 14.1 volts and without the fuse installed the load side fluctuates between 11.6-12.6 volts. Of course this disappears when the main switch is turned off. This is all supported with the starting batteries and is supplies the front of the coach, dash lights, turn signals, outlet sockets, etc. Share this post Link to post Share on other sites
abyrd Report post Posted February 4, 2016 There should be no voltage on the load side of the fuse holder with the fuse removed. Do you have the leads on your volt meter with one lead to ground and the other on the fuse holder? Jim Share this post Link to post Share on other sites
blakeloke Report post Posted February 4, 2016 The corrosion you mention could be a normal condition if you live in a humid environment. I would clean the terminals with anti-corrosion lubricant, an old toothbrush and some emery cloth. Check for pitting on the fuse itself. If pitted replace fuse with a new one. As Jim states above, you should have zero voltage on the load side when the fuse is pulled. Share this post Link to post Share on other sites
ridgeviewroad Report post Posted February 4, 2016 The corrosion problem confuses me because it occurs on only part of the fuses. Yes the black lead is to ground and using the red to check both sides of the fuse holder. I have remove each of the other fuses one at a time to trace the source of the bleed over but still can not identify where it is coming from. Share this post Link to post Share on other sites
abyrd Report post Posted February 4, 2016 My next step would be to remove all of the fuses and with your voltmeter leads from ground to the load side of the circuit in question, now start installing the fuses and read and record the voltage after installing each fuse. If you find that the voltage only occur when one fuse is installed then you can start troubleshooting that circuit. If the voltage value increase with the installation of each additional fuse, the trouble shooting will be more difficult. If this is the case, I would clean the fuse block with an electrical cleaning solvent and dry toughly and then retest.Good luck with your endeavor.Jim Share this post Link to post Share on other sites
rossboyer Report post Posted February 4, 2016 I would check for a bad ground in the parking, running, and tail lights. Because of their location, water enters into the sockets and will cause a lot of gremlin problems. Share this post Link to post Share on other sites
Lenp Report post Posted February 5, 2016 While a voltmeter is a valuable tool when troubleshooting electrical problems, a trouble light can be even more valuable. I would guess that IF you used a trouble light on both sides of that fuse location (with the fuse removed) only one side would illuminate the trouble light. The voltage your reading on the load side is simply leakage from (as previously noted) a corroded socket or something similar. I once had a 12 outlet (cigar lighter) that had a 12 volt reading with a voltmeter (between the center pin and the sleeve) but when a phone charger was plugged into it, the phone would not charge nor did the little LED on the plug light up. I discovered a blown fuse for that circuit. The DC distribution panel had the LEDs that were supposed to tell you if a fuse was blown, BUT they only light up when a load is attached providing a path for current flow With no load, the LED stayed dark but it still passed 12 volts to the outlet. Sure had me fooled for a while. A trouble light would have caught it immediately. Also great for checking fuses - simply probe each side of the fuse and if the fuse is good, the light will light. Another tip for ensuring a good ground for the trouble light - get a 120 AC plug (three prong) and attach a long wire to the ground (round) connector and use that for your trouble light ground. Leave the other two (flat) connectors un-connected. This solves the problem of finding a good, known ground. Lenp Share this post Link to post Share on other sites
kaypsmith Report post Posted February 5, 2016 Lenp, reminds me of when I used to repair rf amplifiers, I used a 300 watt light bulb screwed into a lamp base in the circuit, removed one tube at a time until the lamp no longer lit to find the culprit. Also on later solid state, worked equally well. Kay Share this post Link to post Share on other sites
nitehawk Report post Posted February 5, 2016 Just don't do what happened to me many years ago. I had no juice to the taillights at all. (door hinge bolt pinched a wire)This after bodywork done to repair a T-bone to the driver's side. I went to a nearby gas station, got out of the car, the attendant asked what the problem was. I told him I had a short and needed some fuses. When I came out of the station there was bitter black smoke roiling out of the car. The blasted attendant said he held a pliers across the fuse holder to find the short. When I got home and crawled under the dash all, ALL the wires insulation was melted! Share this post Link to post Share on other sites
kaypsmith Report post Posted February 5, 2016 Hope you sued the gas station, they were responsible for their employee's action. That's why you must use a resistive load for testing, be sure the wattage of the test light is less than the fuse that you are testing. Share this post Link to post Share on other sites
jleamont Report post Posted February 5, 2016 Haha, I had a mechanic at a dealership do the same to a brand new Lincoln LS just off the car carrier for PDI. The sunroof kept blowing fuses, so he jumped the fuse with a paperclip and "was going to smoke out the short" so he explained to me afterwards. The headliner caught fire behind him while he was sitting in the drivers seat looking forward, little beads of fire were dripping onto the back seat. FOUND IT! Factory pinched the harness in the headliner access panel. Share this post Link to post Share on other sites
kaypsmith Report post Posted February 6, 2016 In radio lingo, smoke is the magic that makes the radio work, if you let it out, radio ceases to work. Back to the original post, the higher the amp draw through a fuse terminal, the more likely you will see corrosion sooner than the lower amp draw terminals. Share this post Link to post Share on other sites
ridgeviewroad Report post Posted February 12, 2016 Sorry, I have been gone for a few days. But, I did find the source of the current is the solar panel which feeds the battery when in storage. When I pull the 6 cluster plug, which includes the wiring for the solar panel, it all clears up. Still can not find the culprit causing the short to the remaining load side of the fuse holders. I think I will start pulling bulbs as suggested above to find a grounding issue. Thanks for all the helpful post. Dennis Share this post Link to post Share on other sites
hermanmullins Report post Posted February 12, 2016 Dennis, It just came to me. Have you changed out a 12 volt light bulb recently? All the bulbs that are 12 volt are double contact. if you or someone changed out a bulb and used a single contact (single contact single element) bulb you may have a dead short in the socket. In an automobile all light sockets are grounded (-) through the socket wall and the center contact is the power (+). While on an RV the light socket has separate Ground and power leads and not grounded through the socket wall. I hope I have made some sense cause I may have even confused myself. Just my thought and besides if I am wrong I can blame it on the lack of sleep (aka nap). Herman Share this post Link to post Share on other sites
