1998 SE electrical problems

[stoshe2003]

I have a 1998 maxima SE About 2 months ago i noticed that it overheated once( or at least the temp gauge indicated that it had overheated) I bought a new thermostat/neck from advance auto and installed it and flushed the system. The problem came back a week later so i took out the thermo/neck and went to the nissan dealer and got their neck thinking maybe advance one was junk, and i installed it and flushed system again. This time the problem was back even sooner. the temperature gauge(no other guages as of yet) would act very sporadic heating up and cooling down in a fashion that i know is not possible actually. I took it to a shop where they shot the block with a laser thermometer and told me the car is not overheating(the gauge was pegged in the "H" when i was there) and they also told me that my fans were working normally. the gauge continued to act sporadic the next few days until it had a really bad episode where my engine light came on and it pulled a knock sensor code(which im told it always does)and a PRNDL sensor code. I took it back to the shop and they cleared the codes. At this point it seems like whatever the problem is it is progressively getting worse/causing more problems including the overdrive shutting down while im driving. I noticed that the car barely wants to start at times and i began thinking maybe the battery was bad and a lot of the electronics are starving for power when i am driving. I realized the battery was the same on that i had since i bought the car 4 years ago so i went to walmart and had them put in a new battery even tho they tested the old one and said that it was good. During this trip i noticed something new. The more electrical devices i turn on in my car the higher the temp gauge goes and if i pull up on all the power window switches at once the temp gauge FLIES right up to "H" (but only at times, not always, there are times where it is unaffected) then just today after a whole aggravating several hours of these problems i stopped at a gas station where the battery did not have enough power to restart the car. I had someone jump the car and i went to walmart for them to retest the battery. they said the battery is fine but the alternator is not putting out any charge. I then went to advance auto during which time on the trip there, the temp gauge went back to normal and when i got to advance auto to order an alternator they said that mine was fine. This type of intermittent problem is going to drive me nuts. Any suggestions. Anyone know if the voltage regulator is inside the alternator or elsewhere? I think my next step is going to be to replace the alternator even tho im unsure if it really needs one. can anyone help me or ever experienced anything like this?

[jltibbs]

personally, i would start with the coolant temp sensor [temperature switch/sending unit(part number 385167 at advance auto parts)]. then i would replace the alternator (part number 13402 at AAP). next i would replace the knock sensor (part number KS79 at AAP). if after all of that you still have problems, i got nothin.

[stoshe2003]

Well i got the alternator out today, that was a PITA.It tested fine at advance. I ordered a new one for 214.00 even though i dont need it. Picked up a coolant temp sensor and put it in. When i was taking off the alternator i discovered some kind of ground wire which grounds to some of the metalwork on the top mounting bolt of the alternator, and also has a harness that runs thru it. That ground was basically corroded off and hanging on by a thread, i dont know what that ground does if anything significant but ill be putting in a new one there and re-attaching it to a new spot on the fenderwell. Does aluminum ground things or is that ground for the alternator? Apparently i wasnt awake that day in science class because i cant recall. I also discovered some kind of sensor that goes into the engine head or crankcase right above the tensioner that is leaking something like, i think oil. Anyone know what this sensor is and should i be concerned?

[seabob4]

Hey, Bud. What you have is a basic ground problem. 99% of all mobile electrical issues are ground related. I work in the Marine business, and when you said that the ground wire was corroded off, pull that wire and strip off another 6" of insulation. What does it look like? Is there evidence of a blackish color? Corrosion has a wonderful tendency to wick it's way up a wire. Even if the wire looks good and feels solid, resistance is your enemy here.

My advice? Find what device is being grounded and replace the entire length with 10 GA stranded Marine wire. One has to remember; 12V systems are basically a circle, with voltage going out from the batt., and the same voltage coming back. If there is an obstruction in the return path, that voltage will seek any path it can find to get back to the batt. I have seen some of the wierdest things happen on boats because the ground leg was looking for a place to dump its energy. See if this works, 'cause it sounds like you've got some really weird s*** going on here. But the dead giveaway is your temp gauge pegging. Give it a try!

[seabob4]

Oh, and by the way, I don't think you need a new alternator. Don't waste the $214!