dodge truck question

[wagesofsin]

ok checked it today it was 12.7 volts not running and 14.9 running it didnt change while reving!! so i guess its not the alt!!

regulator is in question though, shouldnt crank over 14.5 even on a dead battery. id replace that.
this may sound dumb, but disconnect the positive battery lead while its running. if it dies, the alternator is malfunctioning. it may sound like urban legend, but if the alt is good, it will stay running.
of course if the regulator is bad, it may not be the case, im no expert, just trying to help.

[Aussie Challenger]

  DON'T  DISCONNECT ALTERNATOR  WHILE  ENGINE IS  RUNNING  YOU  RISK  BLOWING  ALTERNATOR.
  I would live with 14.9 volts however it shows that something is drawing alot of current, start checking for a short, have you checked the wires on the back of the amp guage?

[Mr. 6pak2go]

no i havent checked yet im gonna check today! so if i start pulling fuses and the volts drop from 14.9 than thats the problem area right??

[wagesofsin]

  DON'T  DISCONNECT ALTERNATOR  WHILE  ENGINE IS  RUNNING  YOU  RISK  BLOWING  ALTERNATOR.
  I would live with 14.9 volts however it shows that something is drawing alot of current, start checking for a short, have you checked the wires on the back of the amp guage?

hahah, who said that?

i didnt see anything about disconnecting the alternator   

[Mr. 6pak2go]

ok i checked again 12.7 not running 14.4 running i pulled all the fuses and nothing changed it was still between 14.4-14.6! everything seems to be running fine i drove it all day yesterday no problems so far iv put close to 400 miles on the new battery no problems it had to have been the cab lights that caused the problem!

[wagesofsin]

well, thats awesome.
congrats.

[Aussie Challenger]

 

  DON'T  DISCONNECT ALTERNATOR  WHILE  ENGINE IS  RUNNING  YOU  RISK  BLOWING  ALTERNATOR.

  Just reviewing what I wrote, I meant to say DON'T DISCONNECT THE BATTERY.
  Hope this clears up my mistake.   

[Mr. 6pak2go]

ok more problems check this out i drove my truck night before last and noticed everything behind me was unuasally dark pulled ove to discover none of my rear lights are working in expection of my plate lights ! ok the front lights are fine headlight side and signal all work i know its not the bulbs becouse when i cut on my turn signal (left or right doesnt matter) all four of them blik like i cut my hazzerds on?? but the back ones are really really dim and my gas hand mysterously quit working?? any ideas??  oh ye achecked all fuses and grounds everything ok and i checked all the the connections everything seems fine and i checked the left and right connections in the circet board!! please help!! thanks kevin

[Mr. 6pak2go]

ok this makes no sense to me i checked the voltage at the plug near the rear lights both sides are geting 2 volts im gonna try rplacing all the bulbs is it possable all the bulbs blew at once?? and what kinda volts should i be getiing 2 doesnt seem right to me!!

[Aussie Challenger]

  Definetly got a ground problem at the rear if the voltage is only 2 volts, check ground straps from chassis to body. If not sure run a wire from the earth on the battery to the rear tail light body and see if lights brighten up.
  Yes it is possible for all globes to blow at once but in this case I am sure that is not the problem. The alternator would need to be charging 18 + volts at least.
  Min. of 12 volts at the rear, usually the same as the battery voltage.

[Chryco Psycho]

I agree the tailights are nto grounding

[Mr. 6pak2go]

oh i was working on it again tofay and its only geting 3-4 volts comeing out of the turn signal switch in the steering colume could the switch be bad??

[acudanut]

  Have you checked to see what the alternator is charging at idle and at say 2,000rpm. At idle it should be around 13 volts, at increased rev's go up to between 13.8 & 14.5 volts. A loose or slipping fan/alternator belt can cause fluctuations at low rev's, I would check the ground on the alternator panel, I run a wire between that panel and the battery Neg terminal, eliminates most of those problems.   
  Having said all the above if you have a decent short in the system you will also get the lights dimming as you described.   
  Don't disconnect the alternator while the engine is running you can "blow-up" or fry the alternator, it needs a voltage source to tell it how much voltage to put out.   

Negative, the alternator, does not need a voltage source to tell it how much voltage to put out.   It does not think or calculate anything, it just puts out voltage period.  The voltage regulator is the only thing that does such a thing.
Also, if your Dodge truck is a 72-79, this is a VERY common problem.

[Chryco Psycho]

I assume you are getting 12 v into the switch , if si yes the TS switch os a problem

[Mr. 6pak2go]

ok replaced the switch didnt help theres 12 coming in and out its gotta be after the switch how about the head light switch??