rabbit Posted April 22, 2020 Share Posted April 22, 2020 1984 Horizon coach won't charge with shore power or alternator. Fuses are all good. Not sure what to check next Quote Link to comment Share on other sites More sharing options...
Derek up North Posted April 22, 2020 Share Posted April 22, 2020 Have you owned for long? Is this a new problem? Do you have a multimeter? Quote Link to comment Share on other sites More sharing options...
rabbit Posted April 22, 2020 Author Share Posted April 22, 2020 2 hours ago, Derek up North said: Have you owned for long? Is this a new problem? Do you have a multimeter? Quote Link to comment Share on other sites More sharing options...
Odyssey 4x4 Posted April 22, 2020 Share Posted April 22, 2020 Start tracing 12V from your running truck's battery through the isolator to fuse block and see where the power stops Quote Link to comment Share on other sites More sharing options...
Derek up North Posted April 22, 2020 Share Posted April 22, 2020 So it appears your alternator is working since the truck battery. While NOT plugged in to shore power, I would 1st use your multimeter to see if 12v is exiting your battery isolator towards the 'house'. There should also be a circuit breaker near the isolator. The wire from the isolator will either go directly to the house battery or (I suspect) go to a terminal on your converter and then another wire from the converter to the house battery. That seems to depend on the manufacturer. I've seen it done both ways. Continue on to check the voltage at the house battery. There should also be another circuit breaker near the house battery. Of course check all wires and connections for looseness and damage. Do you have access to a stand-alone 12v battery charger? Try charging the house battery. The house battery might 'bad'. Hint. Before disconnecting any wires from the house battery, mark them so you'll know where to reconnect them! Quote Link to comment Share on other sites More sharing options...
rabbit Posted April 22, 2020 Author Share Posted April 22, 2020 3 hours ago, Derek up North said: Have you owned for long? Is this a new problem? Do you have a multimeter? 15 minutes ago, Derek up North said: So it appears your alternator is working since the truck battery. While NOT plugged in to shore power, I would 1st use your multimeter to see if 12v is exiting your battery isolator towards the 'house'. There should also be a circuit breaker near the isolator. The wire from the isolator will either go directly to the house battery or (I suspect) go to a terminal on your converter and then another wire from the converter to the house battery. That seems to depend on the manufacturer. I've seen it done both ways. Continue on to check the voltage at the house battery. There should also be another circuit breaker near the house battery. Of course check all wires and connections for looseness and damage. Do you have access to a stand-alone 12v battery charger? Try charging the house battery. The house battery might 'bad'. Hint. Before disconnecting any wires from the house battery, mark them so you'll know where to reconnect them! Quote Link to comment Share on other sites More sharing options...
rabbit Posted April 22, 2020 Author Share Posted April 22, 2020 I checked the isolator, 12 v coming from alternator wire to isolator, 7v going to house battery from isolator, is isolator bad? Does it have anything to do with shore power charge system? Quote Link to comment Share on other sites More sharing options...
Derek up North Posted April 22, 2020 Share Posted April 22, 2020 7v going towards the house is certainly not s good sign, though it wouldn't/shouldn't have anything to do with your converter not charging the house battery. House battery voltage with engine not running and not plugged in? Then again when plugged in? Quote Link to comment Share on other sites More sharing options...
rabbit Posted April 22, 2020 Author Share Posted April 22, 2020 Same same. Should I check isolator with engine running? Quote Link to comment Share on other sites More sharing options...
Derek up North Posted April 22, 2020 Share Posted April 22, 2020 47 minutes ago, rabbit said: Same same. Should I check isolator with engine running? "Same same" doesn't really tell us much. Yes, the battery isolator needs to be checked with the engine running and not plugged into shore power. Quote Link to comment Share on other sites More sharing options...
rabbit Posted April 22, 2020 Author Share Posted April 22, 2020 Sorry, same same meaning I checked the isolator with it plugged in and not plugged in however the engine wasn't running. It's beginning to rain quite hard here so I'm going to postpone this till later thanks I'll try the test with the engine running and check back with you Quote Link to comment Share on other sites More sharing options...
Odyssey 4x4 Posted April 22, 2020 Share Posted April 22, 2020 You need to test it with the vehicle running, the isolator is "closed" when engine is off and shouldn't be sending any power to coach battery. Turn truck on, isolator opens, isolator should send 12v+ to coach battery. Some smart isolators won't send power to coach battery until truck battery is at a certain "charged" voltage. Quote Link to comment Share on other sites More sharing options...
rabbit Posted April 22, 2020 Author Share Posted April 22, 2020 Thanks, yeah I tested it with the engine running and it's 15 coming from the truck battery 15 coming out of the alternator to the isolator and then the isolator wires going to the house battery 7. This still doesn't solve my Shore power charging problem I don't think Quote Link to comment Share on other sites More sharing options...
rabbit Posted April 22, 2020 Author Share Posted April 22, 2020 Would any of the fuses underneath the dash in the truck cab have anything to do with this. The last time I drove it the fuse blew for the running lights and the dash lights this fuse was only a month or two old so I think there might be something causing all this perhaps they're related Quote Link to comment Share on other sites More sharing options...
Odyssey 4x4 Posted April 22, 2020 Share Posted April 22, 2020 (edited) 39 minutes ago, rabbit said: Thanks, yeah I tested it with the engine running and it's 15 coming from the truck battery 15 coming out of the alternator to the isolator and then the isolator wires going to the house battery 7. This still doesn't solve my Shore power charging problem I don't think As previously mentioned, if your wire from your isolator was going to the charger/converter rather than directly to the battery, it certainly would explain the shore issue if the charger/converter is malfunctioning. Isolator should be putting out more than 7 volts too. Edited April 22, 2020 by Odyssey 4x4 Quote Link to comment Share on other sites More sharing options...
Maineah Posted April 23, 2020 Share Posted April 23, 2020 The isolator is generally controlled by a wire connected to the wiper motor so if the wipers don't work the isolator won't. With the key on or engine running you should have voltage at the small terminal of the isolator that is what closes the relay. 7 volts on the voltmeter is probably phantom voltage. The wire connected to the coach battery (big terminal on the isolator generally right side) should have voltage regardless running or not if it does not the truck will not charge the coach battery. Often the heavy wire to the coach is fused by an inline fuse with a 30 amp fuse, the proper placement would be at the coach battery but no guarantee. Once the engine is on you should have something close to the same voltage both sides of the isolator terminals and the small terminal. The coach battery should have 2 #8 wires connected to the coach battery + terminal one is the shore power the other goes to the isolator. If you have a box looking isolator (much larger with 3 or 4 wires) that is a bit different. If so let us know and I'll try to talk you through that. Quote Link to comment Share on other sites More sharing options...
WME Posted April 23, 2020 Share Posted April 23, 2020 (edited) Here are some diagrams for different isolators...https://www.custombatterycables.com/battery-isolators/ Edited April 23, 2020 by WME Quote Link to comment Share on other sites More sharing options...
Maineah Posted April 23, 2020 Share Posted April 23, 2020 Being an 84 it could have a 4 wire solid state isolator also. Quote Link to comment Share on other sites More sharing options...
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