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SierraJoe · 01-26-2020, 02:30 PM

I started the RV this morning during it’s winter nap to keep things flowing and the engine died with no current to the electrical system. I did notice a burnt wire smell after it died. I bought the RV last May and have had it out twice. I’ve slowly been replacing old worn components and the engine (440) runs great. Looks like the previous owner replaced the alternator 2 years ago. I have noticed that the amp gauge jumps around from charging to discharging. It looks like the wire going into the harness on the firewall has been replaced and wiggling it will sometimes make it start charging. When the engine died I noticed the amp gauge was jumping around. I disconnect the harness but saw nothing burnt there. Also pulled the instrument cluster and didn’t see any burnt wires into the gauge. Next step will be to check fuses and see if there are any fusible links that blew. Glad it happened at home, but having fun restoring it!

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richard5933 · 01-26-2020, 03:02 PM

First thing I'd do is trace that loose wire and get it taken care of. If it's part of the ignition circuit, it's likely the cause of your problem.

Wiring issues can be problematic, but if you stick to a systematic approach and follow one circuit at a time things can be worked out.

If this is a '77 Dodge, there's a chance it still has a distributor. If so, I believe that the whole ignition wiring system boils down to a hot wire to the coil, possibly with a resistor in series. If that's what you've got, you can always run a temporary feed from the battery to the ignition + side of the coil and see if you can get it started.

There should be lots of information online about these engines. I love the simplicity of them compared to a modern engine.

SierraJoe · 01-26-2020, 06:20 PM

Thanks for the advice. After disconnecting the wiring harness and retightening the bolts on the connections of the wire connections into the amp gauge, it started right up. I also had the instrument panel hanging and as I was pushing it back into place, the engine for a split second sounded like it was going to quit. I got everything reconnected and it started right up again. My guess is something amiss with the connections going into the amp gauge or the gauge itself. I think my next step will be to hook up an external amp gauge. I already have an external water temperature gauge as none of the other gauges work. I had looked into replacing the entire instrument panel, but found no aftermarket ones and the only ones available are on eBay and are 43 years old. External gauges seem the way to go. The wire I thought was loose going into the warning harness was actually hot coming from the cab side going to the alternator from what I can tell.

richard5933 · 01-26-2020, 06:29 PM

Spend some time hunting down every ground connection you can find. They will be all over - battery box, light sockets, gauge cluster, engine ground strap, etc. I'd bet that 90% of electrical problems on an older vehicle, especially one that sits idle most of the time, can be traced to bad grounds. Don't just look at them either - remove the screw/nut/bolt and clean both sides of everything in there. Make sure that the grounds are all made to clean chassis metal.

For the other areas, plugs, and such, there is a product called DeOxit D5. It's designed for cleaning the oxidation off electrical connections.

StevefromPA · 01-26-2020, 06:30 PM

I might think about replacing the ammeter with a voltage gauge. On a vehicle with an ammeter the entire charge flows through the ammeter. No manufacturer uses them any more. A voltmeter will give you the info you need as far as charging. Replace the wire with the bad connections with a straight thru wire eliminating the ammeter.

SierraJoe · 01-26-2020, 07:01 PM

Thank you! I'll look for all the grounds and clean the connections. I also think I will get rid of the amp gauge. From what I have read, they can be a fire hazard with modern alternators with the amps they put out compared to the original alternators and I definitely could smell something hot when the electrical system shut down. Safety first, I've already replaced all of the fuel lines and put on 6 new tires. Thanks again for the advice.

fasteddy · 01-27-2020, 02:14 AM

I have a 1984 Dodge Class B with a 318. I have replaced the alternator 9 times and the voltage regulator 7 times and 3 batteries that were ruined by over charging in 7 years.

After a lot of reading I found out on a Dodge forum that the amp meter has to be removed from the dash board. It shorts out the system. It's a know problem in Chrysler products from the 1960's up until they put the voltage regulator in the computer. To cure the problem in the computer installed voltage regulator you have to install an external voltage regulator.

Then my nephew who does a lot of vehicle rewiring told me to use a one wire alternator. The regulator is wired into the alternator internally and there is just a wire to ground and a wire to the positive side of the battery. I remover the stock regulator to be safe.

It starts every time and in a year and a half there haven't been any problems. I wired a volt gauge into the system.

SierraJoe · 01-27-2020, 09:42 AM

Quote:

Originally Posted by fasteddy

I have a 1984 Dodge Class B with a 318. I have replaced the alternator 9 times and the voltage regulator 7 times and 3 batteries that were ruined by over charging in 7 years.

After a lot of reading I found out on a Dodge forum that the amp meter has to be removed from the dash board. It shorts out the system. It's a know problem in Chrysler products from the 1960's up until they put the voltage regulator in the computer. To cure the problem in the computer installed voltage regulator you have to install an external voltage regulator.

Then my nephew who does a lot of vehicle rewiring told me to use a one wire alternator. The regulator is wired into the alternator internally and there is just a wire to ground and a wire to the positive side of the battery. I remover the stock regulator to be safe.

It starts every time and in a year and a half there haven't been any problems. I wired a volt gauge into the system.

That would explain why I had to replace the one year old battery and the new alternator installed in the RV. I'm going to bypass the amp gauge and install a volt gauge. From what I have read, to bypass the amp gauge I need to splice the wires together that went into the amp gauge. I didn't realize that both wires connected to the gauge were both hot. That would make sense why it's a fire hazard.

StevefromPA · 01-27-2020, 06:16 PM

Yes, so when you connect them make sure you solder them, no butt connectors. They will only build up heat.

fasteddy · 01-27-2020, 09:41 PM

My amp meter was connected to a printed circuit so I removed it from the dash board.

ihc1470 · 01-28-2020, 11:18 PM

One other area to look at is the firewall connector for the amp circuit feed. The connectors are not the greatest and with high amps it will melt things. On mine I ran the alternator directly to the battery. That kills the amp gauge from reading correctly of course as you no longer are pushing the charge current through it. However you also get rid of the voltage drop issues the way it was originally wired.

I plan on pulling the dash and replacing the amp gauge with a volt meter. I have a gauge made up for replacement. If that is successful I will post some pictures of what I did here on this forum.

SierraJoe · 02-08-2020, 06:59 PM

I got around to bypassing the amp guage today. While I was disconnecting wires, I noticed that there was a 20 amp circuit breaker connected to the black wire amp post with a small gauge wire going to a harness connected to a relay on the back of the instrument circuit board. The connection on the relay plugged into the headlight switch. Turns out the wire supplies power to the tail lights and marker lights. I ended up removing the circuit breaker and splicing the wire into a 12 volt wire of the same gauge that powers the light on my external temperature gauge. Once everything was put back together, the RV started right up and the side lights and marker lights worked. I'm not a electrician but I suspect that the tail lights and marker lights might draw a lot of amps and that is why there were fed into the 10 gauge wire. I'm planning to switch my marker and tail lights to LED in the future so I might be alright with my new wiring setup. The previous way it was setup looked very Mickey Mouse to me. On Amazon I found a USB charger that plugs into the cigarette lighter that monitors volts.

richard5933 · 02-09-2020, 12:49 AM

That is an odd way to tap power for the tail/marker lights. Might be a good idea (LED or not) to run that circuit through a relay and keep the 10 ga wiring as direct between fuse box and lights as possible.

SierraJoe · 02-09-2020, 09:03 AM

Quote:

Originally Posted by richard5933

That is an odd way to tap power for the tail/marker lights. Might be a good idea (LED or not) to run that circuit through a relay and keep the 10 ga wiring as direct between fuse box and lights as possible.

I kept the wire connected to the relay, but didn't feel safe splicing the wire from the relay into the 10 gauge with so many amps running through it so that was my thought on choosing another power source. I can tell someone in the past had made some changes to the wiring into the instrument cluster, so my first thought was someone had changed the connection to the marker lights. Looking at the service manual, I saw this was the original configuration for the Dodge B300 van and not unique to the RV conversion. I'm curious why the the connection was not through the welded splice like the diagram shows for most old Mopars.