Hello i have a 1984 dodge ram 150 power ram prospector, and i have a serious alternator issue. First off give ya a little background, i have replaced the alternator 3 times, the batt will be replaced 4 times tomorrow , and the power regulator replaced 3 times. Now i have tried both the 100w and the 65w alternators, im still fryin batteries, also i have found one cable (that seems to go to the power regulator) that is melted at the alternator, this is the second time i will have to repair the connection. i am at a loss here, i have chkd the line itself and it looks good, what could be causing all my issues and where should i be looking cause i obviously aint looking in the right places

Please help I would hate to take it to a mechanic when i know its got to be something simple im missing.

 

Have two feild wires. One come from the ign. switch to one post on the regulator,spliced from there to one post on alt feild. Other alt. feild wire goes back to reg.

Regulator MUST have good ground to the body, or better yet a wire ran to the back of the engine. If a bad ground is present the reg. allows full charge from the alt. Result fried batteries, wiring.

Also you said one feild wire is fried. Strip the harness between the alt. and reg. and be certain a feild wire is not grounded to the engine, or melted to another wire. Take a close look at all connectors as they are prone to frying also.

 

ok so, batt is frying from over charging, regulator is attached to firewall, looks like where it bolts to the firewall gives a good ground, cable that melted is the one that goes to regulator, replaced the regulator and the cable connection that melted at the alternator, it is not touching anything else. I did look over the cable doesnt look like its grounding to engine but will have to wait till i get more time then will replace the entire wire from the alternator to the regulator. is this kinda what you are talking about?

 

How many volts/amps is it putting out? Charging full load all the time? I assume from your info it is.

If the feild was shorted in the 1st alt. that went bad,and fried the wire and regulator then all subsequent repairs are moot until the wire is repaired. If the wire was fried/grounded in the harness someplace to begin with, all subsequent repairs are moot. Strip the harness,or use a multimeter,check the feild wires first.

The firewall may or may not provide sufficient ground for the regulator. Depends on how good the rest of the body grounds are,and how clean the mounting surface is. Add the extra ground,might help,won't hurt. I had a '70 Challenger,and an '83 pickup both that had ground problems at the reg. The Challenger burnt all the bulbs in the dash lights from the juice. Lucky it didn't fry the harness and burn to the ground.

Simple test. Unplug the regulator,if the alt. still charges then the feild/regulator circuit is grounded. If so,unplug the feild to regulator wire at the alt. If it still charges the feild in the alt is shorted to ground. If quits charging by unplugging the reg. then you likely have a bad ground.

 

lugnuts,

Simple test. Unplug the regulator,if the alt. still charges then the feild/regulator circuit is grounded. If so,unplug the feild to regulator wire at the alt. If it still charges the feild in the alt is shorted to ground. If quits charging by unplugging the reg. then you likely have a bad ground.

Can you explain that more for a newb. I unplugged the regulator, and I dont see any chargning. I only have a connector with 2 wires to the regulator, Im not sure what you mean about removing the field wire, after I have already disconnected the regulator.

thanks,
dib

 

If the feild to regulator wire is grounded,or alt feild is grounded internally unplugging the reg will have no effect. The alt will still charge at full output. Since it quits charging by unplugging the regulator,the problem is 98% probability at the regulator. Did you try a ground wire from the regulator mounting bolt to the engine block? Or better yet straight to the neg batt post? Do you have a clean ground wire between the neg post and the core support next to the radiator?

Again,you should have a switched 12v wire at the reg,and to one feild post on the alt. The other alt feild post goes back to the reg. The reg controls alt. output with the second wire by varying the ground of the alt feild. The large third wire is of course the batt charge wire.

The reg is calibrated for zero ohms resistance ground of the reg body. No or poor ground of the reg means the calibration is screwed. It will overcharge a little or a lot depending on quality of the ground.

Also, if the switched 12v wire has low voltage, then the calibration is screwed. Must have full batt. voltage to the reg. Should be no more than 1v difference between the switched 12v wire at the reg,and the voltage at the battery. Any more indicates high resistance in the 12v circuit.

Without knowing for sure how many volts are being fed to the battery we're kinda chasin' our tail. Check it. Should stay at around 13.2v idling to no more than 14.2v revved up. With a hot battery it should stay closer to 13.8v revved up.

14v or more with a hot battery, engine revved up indicates a poor ground or a reg/feild/wiring/12v reg supply wire problem. 14v or more at idle means you have a real bad problem lol.

 

Lugnuts , Draco ,
If Im thread jacking tell me to hit the road . Just seems we are working on similar issues. So I opened the wiring harness from alt. to reg. Looks good, no shorts that I can see. My Ohm meter only read in 1K units , its for house wiring and such. It says i have 1k ohm resistance between the body of the voltage reg. and the negative terminal on my battery. Is that ok? When i put the leads directly to each other i get 0K ohm. Might I need to make a better ground? Or does the regulator sounds grounded well enough?

thanks a bunch,
dib

 

Sorry , I made an error. I have 0k ohm resistance between the body of the regulator and the positive terminal. I have about 13K ohm resistance between the body of regulator and the negative terminal. Is that OK?

thanks,
dib

 

Should read practically zero given the amount of sheetmetal in a truck body to carry the current. Check the firewall and see what you get. Then check between the engine and the batt. The neg cable is big enough it should read practically zero. If the firewall has resistance and the engine doesn't,add a ground wire from the reg to the engine. If the engine has resistance, check the neg cable. And clean the ground wire at the core sppt. too.

 

thanks Lugnuts! I got some 12 guage romex running to my battery from the regulator now. Rev the hell out of the engine and all i saw was 14volt, 13 most of the time. Lights stopped flickering..and it seems the tempature guage is working now....kick ***!!

Thanks A Lot!
dib