HOGIE Posted April 22, 2015 Report Share Posted April 22, 2015 So my 79 620 has a charging issue Edit **I typed this while high on paint fumes from priming the Canby truck** You know, you get a jump to try to get home but as your going up a hill it starts to sputter because the headlights are taking to much juice away from the coil. Then when you try to drive home without the headlights on you get pulled over and have to leave your truck on the side road Take a fresh battery to go pick up the truck the next day I pulled the alternator and installed another IR alternator that I thought was good. I see smoke coming from the alternator. Unplug battery and all the wires to the alternator and fine this Why? Possible senarios 1)The battery was near dead and was one the charger 2)The gauge of the yellow fried wire is smaller than the factor that it is sliced together with 3)some coolant may have dripped on the alternator 4)I put dialectric grease on the L-plug and the grease may have arced current from another wire, see below I then started to see if the correct wires at the alternator had power and ground. Found a weak ground at the WL wire at the L-plug. Used wire diagram and followed the wire back to the auto-choke relay. When harness was plugged in the relay all terminals had the same weak ground, Unplugged the harness and found the ground in one wire. Followed to main cab-to-engine harness plug and found the weak ground on the cab side of the harness and the wire diagram says the wire goes to one place, the charge light.... Okay? Could a grounded charge light cause the wire to heat up so much that it burns though its insulation? Looking for solutions? Ideas? I aslo picked this up to improve my charging system but it is clear now that there is something else at play that needs to be addressed before I install this nice new hardware, 60amp I might be leaving something out, I havent pulled the gauge cluster out yet to get at the charge light, tomorrow Edit **I typed this while high on paint fumes from priming the Canby truck** Quote Link to comment
ggzilla Posted April 22, 2015 Report Share Posted April 22, 2015 Possible senarios 1)The battery was near dead and was one the charger 2)The gauge of the yellow fried wire is smaller than the factor that it is sliced together with 3)some coolant may have dripped on the alternator 4)I put dialectric grease on the L-plug and the grease may have arced current from another wire, see below None of the above Could a grounded charge light cause the wire to heat up so much that it burns though its insulation? Nope. The L terminal on the alternator is the ground. Quote Link to comment
datsunaholic Posted April 22, 2015 Report Share Posted April 22, 2015 L is not ground. E ("earth") is ground. L is the light, but grounding it won't burn the wiring. It is true that L is the ground PATH for the alternator light in the dash, but it goes through the diode trio to get there. Since there's a bulb in line with that wire, it'd take some pretty screwed up wiring AND a screwed up alternator to do that. Basically the alt light would have to be replaced with a shunt and the diode trio shorted to a true ground. 1 Quote Link to comment
ggzilla Posted April 22, 2015 Report Share Posted April 22, 2015 What is "the L-plug"? Do you mean the T-connector? One thing I'd look at is the "IR alternator that I thought was good". Maybe it is shorted out. The Lamp wire should show 12V when unplugged and IGN on. 1 Quote Link to comment
HOGIE Posted April 22, 2015 Author Report Share Posted April 22, 2015 I thought that the E for earth was the ground as well as the engine block, and batt of course is the hot line from battery WR, ... now what are thefunctions of the two wires that go to the L-plug (T-connector if thats what you want to call it), the S and L terminals? 1 Quote Link to comment
ggzilla Posted April 22, 2015 Report Share Posted April 22, 2015 The E terminal is earth (ground) for the alternator. The L terminal is ground for the dash lamp. 2 Quote Link to comment
ggzilla Posted April 22, 2015 Report Share Posted April 22, 2015 what are thefunctions of the two wires that go to the L-plug (T-connector if thats what you want to call it), the S and L terminals? The connector plug is not L-shaped in any way. * L terminal goes to dash Lamp * S terminal connects to the Sense wire (battery +). I am not sure why Hitachi has a separate sense wire; GM and Lucas just connect the regulator internally to the main BAT terminal. Nissan connects it to the battery in some models and to IGN in other models. 2 Quote Link to comment
banzai510(hainz) Posted April 22, 2015 Report Share Posted April 22, 2015 bad connections can someimes cause a heat melting issue. High resisituve short clean connections 2 Quote Link to comment
harlow426@mail.com Posted April 22, 2015 Report Share Posted April 22, 2015 Hey Subway....err Hogie. U get it fixed? I have complete harness from the 'Alsea' rolled over truck(motor in my DD, tranz Canby build). Let me knoe if your truck still needs help. 1 Quote Link to comment
HOGIE Posted April 22, 2015 Author Report Share Posted April 22, 2015 Is the harness for a 78-79 kc 620? Hey Subway....err Hogie. U get it fixed? I have complete harness from the 'Alsea' rolled over truck(motor in my DD, tranz Canby build). Let me knoe if your truck still needs help. 1 Quote Link to comment
banzai510(hainz) Posted April 22, 2015 Report Share Posted April 22, 2015 dude ck the connections and clean them before swapping out harnesses. sometime swapping out a harness will cause more proplems even if a burnt wire just splice and fix it. 1 Quote Link to comment
HOGIE Posted April 22, 2015 Author Report Share Posted April 22, 2015 The E terminal is earth (ground) for the alternator. The L terminal is ground for the dash lamp. Okay, L terminal is ground to the dash bad connections can someimes cause a heat melting issue. High resisituve short clean connections Okay, I'll clean the connection. Should there be any current flow through the alternator when the engine is off? dude ck the connections and clean them before swapping out harnesses.sometime swapping out a harness will cause more proplemseven if a burnt wire just splice and fix it. Just an option, there are more spliced wires than this one Does it make sense that the all wires to the auto-choke relay should be grounded? 1 Quote Link to comment
banzai510(hainz) Posted April 22, 2015 Report Share Posted April 22, 2015 when you turn key to ON. One of the wires in the T connector will excite the alternator. the choke relay? well you cound disconnted the wire and truck should still start and run. Key is do you have a volt meter and if you have this running what is the voltage across the battery. maybe the alt is bad have it cked out. If still bad with another alt then I would look at the wiring. On my 521 I had a fuse pop then no ignition light. Of cuse no charging. Find out I had a bad connction in back of the instrument panel. This is highly unlikkely for your case. Does it make sense that the all wires to the auto-choke relay should be grounded? It might be untill you put the key on. Kinda like the headlights on the 510. all have 12volts on all the 3 lugs but then gets a ground put on to light up the lamps. 2 Quote Link to comment
Draker Posted April 22, 2015 Report Share Posted April 22, 2015 Okay, I'll clean the connection. Should there be any current flow through the alternator when the engine is off? Not unless the alternator is bad. 1 Quote Link to comment
q-tip Posted April 22, 2015 Report Share Posted April 22, 2015 No wiring problems before alternator swap? If so point finger at alternator. 2 Quote Link to comment
ggzilla Posted April 22, 2015 Report Share Posted April 22, 2015 Okay, L terminal is ground to the dash Not correct. L is ground for the Lamp. Should there be any current flow through the alternator when the engine is off? Yes, with Engine OFF, IGN ON, current should flow thru dash Lamp, thru L terminal into internal Voltage Regulator where it is switched to ground. Through the BAT/A terminal, no current should flow when engine is off. Ditto for Sense wire and S terminal. 1 Quote Link to comment
HOGIE Posted April 23, 2015 Author Report Share Posted April 23, 2015 bad connections can someimes cause a heat melting issue. High resisituve short clean connections I rewired the yellow sense wire and the WR auto-choke relay/ charge lamp ground wire at the T connector, with new spade females and soldered them properly. I'm hoping this was just a bad connection or bad alternator issue and it won't happen again with the new alt. Does it make sense that the all wires to the auto-choke relay should be grounded? It might be untill you put the key on. Checked this and yes the WR wire was grounded with key OFF and all wires at auto-choke relay had ground. When the key was ON, no ground. This really got me concerned but I realize it isn't a problem at all now and is normal No wiring problems before alternator swap? If so point finger at alternator. I follow this logic with regards to the wording and the new alternator, but there was charging issues before the new alternator was installed. I have two freshly recharges batteries and I'm going to install a few different alternators and see what the volts across the battery is on each and report back. 1 Quote Link to comment
banzai510(hainz) Posted April 24, 2015 Report Share Posted April 24, 2015 about 45secs in this will trst for battery drain if a short. save this https://search.yahoo.com/search;_ylt=AsfTz8zSEavKOACRjc.YXZCbvZx4?p=you+tube+battery+drain&toggle=1&cop=mss&ei=UTF-8&fr=yfp-t-901&fp=1 1 Quote Link to comment
HOGIE Posted April 26, 2015 Author Report Share Posted April 26, 2015 With the new alternator and wires checked, there is less than 12V across the battery with the truck running. Some other problem to be found Quote Link to comment
ggzilla Posted April 26, 2015 Report Share Posted April 26, 2015 If the wires are checked good, then it must be a faulty alternator. The wires are good if * S wire has 12V before starting the engine * L wire has 12V before starting the engine Both wires tested unplugged from alternator, IGN on, engine OFF * BAT/A wire has 12V while connected Quote Link to comment
banzai510(hainz) Posted April 27, 2015 Report Share Posted April 27, 2015 ck as GGzilla staed. I would ck to see if the alternator is getting its 12volt exiciting voltage. alt needs 12volts to the windings.(my case it lost the 12volts from the dash 521 truck) Quote Link to comment
HOGIE Posted April 28, 2015 Author Report Share Posted April 28, 2015 The other day at Al's, while working on the Canby truck, Al, Edd, and Dan looking at Ratsun. My 620 in the back Later me and Dan, thanks Dan, checked the battery while the truck was running, w/ new alt, and ≈12.2V Got a new belt, soldered the BAT and lamp wire terminals. 14.4V with headlights on. ck as GGzilla staed.I would ck to see if the alternator is getting its 12volt exiciting voltage.alt needs 12volts to the windings.(my case it lost the 12volts from the dash 521 truck) Will check If the wires are checked good, then it must be a faulty alternator.The wires are good if* S wire has 12V before starting the engine* L wire has 12V before starting the engineBoth wires tested unplugged from alternator, IGN on, engine OFF* BAT/A wire has 12V while connected Will check Thanks! Quote Link to comment
banzai510(hainz) Posted April 28, 2015 Report Share Posted April 28, 2015 great got it working. Most times cleaning battery connections should be the first. but most times it wount start when this happens. Quote Link to comment
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