tom'sB2B Posted February 16, 2014 Report Share Posted February 16, 2014 I've been searching the forum and my service manual to educate myself on the electrical system of my truck. I read on one posting that by removing one terminal from your battery while the truck is running it will indicate if your generator is working or not ( if you pull the terminal off and the truck dies, the generator is not working). My service manual says to use a test light between the armature terminal and the ground to test your generator. 1. I removed one the battery cables and the truck died. 2. I tested the generator with a test light and the light lit up. What am I missing? The amp meter in the truck shows about -25 amps..I'm assuming that the battery is being charged. After about 25 min of driving the amp meter basically goes to zero. I never see a positive reading. As a side note. Lately the truck has been totally shutting off when I'm driving. It doesn't happen all the time, but when it does I have to pull over when I can and frantically jiggle the battery cable and turn the key on and off. When I do that I eventually get power again and I can drive off. Its not a fun experience (especially on a curvy country road with my wife in the truck ). I haven't been able to duplicate it in the driveway. I've been jiggling wires and checking connections to no success. Any guidance would be appreciated. Quote Link to comment Share on other sites More sharing options...
_shel_ny Posted February 16, 2014 Report Share Posted February 16, 2014 (edited) Is your battery going dead? If not, your gen is doing something. Output was low on my 51. If the battery cable was removed while idling, it would die. With higher rpms it would stay running when the cable was removed. Edited February 16, 2014 by shel_ny Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted February 16, 2014 Report Share Posted February 16, 2014 (edited) sounds like it is time to go through you electrical system checking for tight clean fitting, good clean tight grounds and do not rule out the very body to regulator contacts make sure these are clean and tight...a systematic step by step in the correct order by the book should get you where you need to be..check your polarity if the battery does seem to charge in a negative indicted manner.. Edited February 16, 2014 by Plymouthy Adams Quote Link to comment Share on other sites More sharing options...
_shel_ny Posted February 16, 2014 Report Share Posted February 16, 2014 Quick check. Engine off. turn on headlights. where is the amp meter needle. Quote Link to comment Share on other sites More sharing options...
tom'sB2B Posted February 16, 2014 Author Report Share Posted February 16, 2014 I get a reading of +25-30 amps when I turn the lights on with the engine off Quote Link to comment Share on other sites More sharing options...
tom'sB2B Posted February 16, 2014 Author Report Share Posted February 16, 2014 Shouldn't the meter read negative when I'm drawing power and positive when I'm generating power? It seems what I'm seeing on my truck is the opposite. Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted February 16, 2014 Report Share Posted February 16, 2014 You said "The amp meter in the truck shows about -25 amps..I'm assuming that the battery is being charged. After about 25 min of driving the amp meter basically goes to zero. I never see a positive reading." Is your battery connected correctly? Positive cable grounded to the engine? Do you have an ohm meter? If so with the engine running at high idle the battery voltage should read around 7.2 volts with a healthy generator. And has been mentioned all cable and wire connections must be tight and all ground connections clean and secure. Quote Link to comment Share on other sites More sharing options...
tom'sB2B Posted February 16, 2014 Author Report Share Posted February 16, 2014 (edited) yes. positive to engine ground, negative to starter connections. Edited February 16, 2014 by tom'sB2B Quote Link to comment Share on other sites More sharing options...
B1B Keven Posted February 16, 2014 Report Share Posted February 16, 2014 Sounds like the amp gauge is wired backwards? Have you tried 're-polarizing' the voltage regulator? Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted February 16, 2014 Report Share Posted February 16, 2014 Sounds like the amp gauge is wired backwards? Have you tried 're-polarizing' the voltage regulator? Actually you polarize the generator but it is done at the regulator. Quote Link to comment Share on other sites More sharing options...
tom'sB2B Posted February 16, 2014 Author Report Share Posted February 16, 2014 I repolarize with ignition switch off...amp gauge jumps to +30 amps. I turn on key, amp gauge moves back to zero. I start engine and amp gauge reads roughly -10 when I accelerate engine. The gauge could be wired wrong (with my mechanical skills I wouldn't be surprised). I'm having a hard time figuring out which terminal on the back of the gauge is positive and negative. I also found that the connections at my ignition switch were a little loose..I'm hoping that might be the answer to my random power loss. Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted February 16, 2014 Report Share Posted February 16, 2014 Did you re-wire your amp gauge recently? Quote Link to comment Share on other sites More sharing options...
Aussie Dodge Posted February 16, 2014 Report Share Posted February 16, 2014 Just a quick one, you need a volt meter not an ohm meter to check your voltage. An ohm meter reads electrical resistance. I am guessing that you use the word ohm meter as a generic name for a multimeter which does a number of functions, including voltage. Quote Link to comment Share on other sites More sharing options...
Jeff Balazs Posted February 16, 2014 Report Share Posted February 16, 2014 Tom......regarding the random cut out issue. You might also want to check your connections at the coil as well as the lead to the distributor and the condition of the wiring insulation and connections inside the distributor. You can see things better if you remove the distributor to check the internals. Jeff Quote Link to comment Share on other sites More sharing options...
HanksB3B Posted February 16, 2014 Report Share Posted February 16, 2014 (edited) Just a quick one, you need a volt meter not an ohm meter to check your voltage. An ohm meter reads electrical resistance. I am guessing that you use the word ohm meter as a generic name for a multimeter which does a number of functions, including voltage. +1 on the multimeter. I keep an inexpensive one in the glve box along with a tire pressure guage (both, basic nessities) Haven't been having that kind of trouble of late so I forgot how to do it. Hank If you're keeping your truck 6V Pos. then having new wires and good connections (preferably soldered) taping over phenolic board and bead blasting the switches is the best start and don't even think about not running a 6V Optima or an Interstate.with the correct cold cranking amps) and good luck. p.s. Hi Jeff (please keep watching my Factory (now Harbor Freight) Brake Job. Edited February 16, 2014 by HanksB3B Quote Link to comment Share on other sites More sharing options...
tom'sB2B Posted February 17, 2014 Author Report Share Posted February 17, 2014 I will get to work on all of the above suggestions. Some of the wiring on this truck is embarrassing to look at. I shouldnt be surprised if had more problems. I will get to work. I would still like to know what side the positive terminal is so I can make sure whether it is wired correctly. Quote Link to comment Share on other sites More sharing options...
Aussie Dodge Posted February 17, 2014 Report Share Posted February 17, 2014 (edited) I believe your ammeter is wired correctly if your truck has the same circuitry as my 48 business coupe.. The ammeter will read negative when the generator is charging your battery. When the battery is fully charged the ammeter will read zero and the Generator will supply the load for everything. As the generator is connected on the load side of your ammeter (where the trucks load is connected) it will not register on the ammeter when it is supplying the load. Generators or Alternators will always supply the load in a healthy system as electricity will flow from it rather than draw from the battery. If you get a positive on your ammeter when the motor is running, it will mean that the battery is being drained & this then means your generator cannot handle the load or is faulty. The only time you should get a positive reading that is healthy, is when the engine is off & you have a load on. ie lights on. I hope this make sense! Regards, Glen Edited February 17, 2014 by Aussie Dodge Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted February 17, 2014 Report Share Posted February 17, 2014 makes no sense...whether your meter is marked + and - and or Charge or Discharge...positive or negative ground...proper polarization and orientation of the amp meter input/output should show any charging state as + or Charge... Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted February 17, 2014 Report Share Posted February 17, 2014 Just a quick one, you need a volt meter not an ohm meter to check your voltage. An ohm meter reads electrical resistance. I am guessing that you use the word ohm meter as a generic name for a multimeter which does a number of functions, including voltage. You are correct, I should have said Multimeter or volt meter. Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted February 17, 2014 Report Share Posted February 17, 2014 makes no sense...whether your meter is marked + and - and or Charge or Discharge...positive or negative ground...proper polarization and orientation of the amp meter input/output should show any charging state as + or Charge... I agree completely. If the amp meter is in the plus side the charging device (generator or alternator) is charging the battery, negative side indicates a drain on the battery as the charging device is not able to keep up with the load. Quote Link to comment Share on other sites More sharing options...
tom'sB2B Posted February 17, 2014 Author Report Share Posted February 17, 2014 So let me see if understand this correctly. If I get in my truck and turn the lights on without starting it, the meter should read negative because the lights are drawing from the battery. I then start the truck I should see a positive reading because the generator is charging the battery. Once the battery is charged the reading should drop down, but still read a slightly positive charge because the generator is creating spark for the engine. If I turn the lights or radio on the meter should the read more positive. By the way, I do think I have it wired backwards. Quote Link to comment Share on other sites More sharing options...
Aussie Dodge Posted February 17, 2014 Report Share Posted February 17, 2014 Sorry!!! You are all correct. I just checked my dodge. (I have only had it a week & the wiring diagram does not show polarity!) The wiring on Tom's truck is connected "back to front" even though It will work either way. It is all a matter of polarity on the Ammeter The way I was thinking:- The ammeter reads positive when there is current flow from the battery to the load & generator. (Battery load) The way Dodge wire it:- The ammeter reads positive when there is current flow to the battery from the generator. (charging the battery) Simply:- the Ammeter should read positive after starting & drop back to zero. This is good You should only get a negative reading with a load on & the motor off, or when there is a fault in the charging system. I stand by the rest of my statements regarding Generators carrying the load. Tom, all you need to do is leave the wires grouped together & swap them over. This will only fix your ammeter reading dilemma! Sorry again fellers! Regards, Glen Quote Link to comment Share on other sites More sharing options...
Aussie Dodge Posted February 17, 2014 Report Share Posted February 17, 2014 Almost correct Tom. Yes the ammeter will read negative with the motor off & your lights on. Yes the ammeter will read positive when you start the motor and it charges your battery Yes it should drop back to zero once the battery is charged. No it should not read positive (when the motor is running and the battery is charged) if you switch any electrical equipment on. The generator is supplying this load & it is connected to the same point as your load wiring on the ammeter. Quote Link to comment Share on other sites More sharing options...
Aussie Dodge Posted February 17, 2014 Report Share Posted February 17, 2014 Oh & you do have it wired backwards as stated in my previous post. Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted February 17, 2014 Report Share Posted February 17, 2014 If it is wired backwards how and when did this happen? Someone had to crawl under the dash and physically change the wires. Why would anybody do this? Was this vehicle changed over to 12 volts negative ground at some point? I am more inclined to believe the battery cables are reversed. 1 Quote Link to comment Share on other sites More sharing options...
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