My Nissan Pathfinder is frying alternators. Tested the battery it is good, checked all wires, fuses, etc.. all good, but I have replaced the alternator twice. Battery is fully charged, put in new alternator and car runs fine for short distance and then everything dims and slows down and amps drop then car dies. Can someone offer a suggestion?
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Charge wire from the alternator to the battery is bad or not connected properly. Check the 120 amp charge fuse link in the underhood fuse box. Voltage at tne battery should be at least 13.5vdc with engine running.
Most likely yes. If you can charge the battery (get it tested after charging as well) up a quick way without any special equipment to find out if your alternator is charging is with as many electrical loads turned off as possible (heater/a/c blower, headlights,heated seats,stereo etc...) Start the engine (after battery is charged) remove one of your battery cables while the engine is running, if the engine immediately stalls your charging system is not charging. If it stays running it is charging. Do not reconnect cable until you turn the engine off to prevent damaging the alternator.
If it stalls the most likely reason is the alternator. There are still other things that may prevent it from charging. Many alternators are regulated by the computer so it could be a computer or a wiring issue or even a blown fuse. If you can remove the alternator without much difficulty then remove it and take it to a auto parts store and have them bench test it. Last but certainly not least make sure your cables are clean inside and out. An alternator cannot charge a battery with poor corroded connections.
There is only three things that would have happened.
1: First check your fuse panel, check all the fuses . if none are dead try the second step
2: take out the alternator, go have it tested, the diodes may be fried. If the alternator is bad there ya go.
3: if the alternator is good (lucky) And it still does not run , then your ECM and PCM are fried. In which case you will have to get new ones which will run a pretty penny ( $500-$1000.00)
you might get lucky and find a set in your local junkyard
good luck and let me know about your alternator
It is not charging the battery because of several problems ---1 when connecting up the wires to the alternator was there a spark at the connection ---2 is the heavy wire on the alternator insulated from the body of the alternator--- is there a fuse in the charge circuit that is blown---4 is the light wires pushed fully home in the connection--- have you the correct alternator for the car ( internal or external voltage regulator)---5 is the drive belt in good condition and tight- If everything checks out then take it to an accredited auto electrician to have the alternator tested properly as new alternators ( out of the box new) can be faulty.
The battery needs 12.6 volts or more to be in service When the engine is running you need 14 volts or more out of the alternator to charge the battery You can test the alt by testing across the battery term or the alt output wire & ground to case or motor Could be the diodes got fried & you need a new alt Have it tested at parts store, if you can't figure it out Check all fuses & fusible links first
Unusual the dealer can't or won't find the problem. A mechanic would check everything in that circuit for shorts to ground. Was the fuse blowing before the alternator and battery were replaced ? Based on the wiring diagrams I would vote for a defective alternator. The 10 amp fuse number 8 powers the cluster which also goes to the alternator. If the alternator shorts out internally it would blow that number 8 fuse and take the cluster with it. The other circuits you mentioned are controlled by the key switch but are fused after the switch. So if the switch was causing the problem it should be blowing a 40amp fuse. I would probably take the alternator off and have someone else test it.
It won't run without a battery, It won't run without the alternator either. I am thinking the battery is dead, or not charging, even the new alternator doesn't mean it is good, Get the battery tested for electrolyte level and voltage, get the alternator tested or at least see if the voltage goes up with with the engine running. Not running, check the terminals on the battery, make sure they are squeaky clean. Voltage above 13+ V. All 6 cells good, check it out. hope this helps.
Check all grounds running from all electrical, If there is not a good contact this problem will occur, when you locate the ground surface take sandpaper or even a knife and scrape or sand the connector and the ground surface then reconnect it, It should return to normal if not then it could be a solenoid possibly but not sure