My son has a 6 year old GM Saturn Vue. For a host of good reasons he is stuck wringing every mile possible out of it before replacing it. It has one elusive issue and problem that keeps Dad at wit’s end and I’d ask this noble bunch for advice for further troubleshooting.
After the car gets warm, say a half to ¾ an hour of driving, the headlights and the heater will pulse a bit. Turn on high beams, or turn on heater fan to ‘Hi’ and it stops. This started maybe 3 years ago. Change the alternator and the problem goes away for about 9 months then comes back exactly as before. We did find an intermittent ground loop on the low speed fan ceramic block and replaced the ceramic resistor 2 times ago.
I somehow think that the alternator is getting stressed by another ground loop somewhere and something goes squirrelly in the output diodes. Make sense? Any advice?
What we talked about yesterday is taking every fuse out possible, and spending a few days putting them back one at a time to ‘see’ when this pulse comes back. Make sense, any advice?
We take too long troubleshooting here and we will be back on daylight saving time and spring. Ha-ha and no real need for heater or headlights as he can use his other car at night.
Looking for ghosts here, or any other advice from personal experience.
Are your replacement alternators coming from the same source? Possibly local rebuilds? Sounds like a voltage regulator, internal, that's not up to specs. The rebuilder may be the problem. Consider another source rebuilt or new.
I should hate to say it, George, but I don't. FordForumsOnline has lots of tales of repeat bad alts rebuilt by the ChiComs. Try NAPA and check the source.
Has it been the same battery through these failures? The battery may be causing the regulator failures.
Thanks so far...
Ed, Good point on the battery, it is the same one since it started and it started the winter after the battery was changed!
Ralphie, no 'hate to say it' involved There is a lot of ChiComm stuff that is still crap on top of crap. But in my own 'hate to say it, but I don't' come back for friendly banter, you do know where Brembo and Benz are now getting all of their brake rotors and caliper holder brackets and caliper frames. (Sorry, couldn't resist the come back...ongoing banter 'tween Ralphie and me).
John, The replacement Alternators have all come from AutoZone, and yes the old ones always seem to check OK on that test thing of theirs. Next one will try another source, just trying to eliminate all other possibilities before trying another alternator...changing an alternator in a Vue is no easy task! That designer should be shot!
The alt should have enough power to kill any device that would be loading it enough to cause pulsing. I suspect its output is intermittent.
I would run a pair of wires from the hot term and case of the alt to a voltmeter in the cabin, and watch it. I would also run a wire from the IGN ON wire where it goes into the alt, to make sure it's not a bad ign source turning off the alt.
Curious George, did you watch 60' last night? Robots are bringing jobs back from the ChiComs, as they take over more repetitive tasks now done by cheap labor.
A dozen years ago I read that if the work were spread equally among all workers, it would be 12 hours per week per person. That number has to be lower now.
George, I don't think the alternator is the problem, from the sound of the symptoms. The problem is 'voltage' related though. I worked for AutoZone (and NAPA), for many years (this is not an endorsement of the product), I am familiar with the way the tester works though and it's not going to try to 'kill' the alternator, it's only going to see if the alternator will do what it's designed to do.
When you say "Turn on high beams, or turn on heater fan to ‘Hi’ and it stops", do you mean the pulsing stops or the car stops? The only thing the alternator does is to provide something like 14 volts charge the battery. If it was a 'direct' alternator problem, the car would continue to function until the battery voltage became too low.
Pull out the heater/defroster fuse first and see what happens. I'm in a little over my pay grade on these 'modern' cars, though.
The pulsing stops...rest of car runs fine. Yeah, think maybe the pull the fuses one at a time or all at once and then put in one at a time may be the next course.
I haven't thought it to be the alternator to date...but I don't know if output diodes can strain or whether they just go and fail and just have found that replace the alternator and the problem goes away for about 9 months. That's the whacko part a new strong alternator masks whatever it actually is.
Open diodes in the alt typically cause a whine in the radio.
I'll bet it's the battery. It takes it a while to kill a good alternator. Try a different battery.
Why would the battery cause that problem?
We had this many years ago in a land far far away. After exhaustive troubleshooting, it was the regulator. Maybe, maybe not on yours.
Trouble with goods from China is they will build it to your specs and price point. Some Saturn's have the alt buried between the engine and firewall. Very hot back there. If you think it is the alternator try one with an OEM regulator and an aftermarket rectifier.
I would make sure the ground wire from the battery to the frame is ok.
We do a lot of Saturn alternators and have not had that issue. Being independent we are a bit picky about the parts we buy and from whom. Do not use an OEM rectifier..!
BTW we repair quite a fair amount of units from the corporate stores. We seldom repair them, mostly rebuild but they often they are low mileage.
We also rebuild for local owners of "these"
types of stores; well for their cars.
Why would the battery cause that problem?
I have seen this problem a few times. The only thing cheaper than speculating about what might/could be wrong, is swapping the battery.
You're experiencing an intermittent load not a short. Does the car have air conditioning? Are you using heat or defrost? On defrost the AC clutch can kick on and off. If it's on the way out it can draw more as it heats up. Un plug it at the compressor the next time the problem happens. The only other on/off load I can think of is the electric cooling fan if so equipped. On a lot of cars the AC clutch and the fan both come on when the AC activates.
By the way: I'm assuming if you turn off either the heater or the head lights and the problem goes away pulling fuses won't tell you a thing as turning them off is the same thing as pulling a fuse because it's not a short.
Could very well be the battery, as you have experienced - I don't know enough to dispute that. I'm just curious...if indeed it is/was the battery, what has happened? - too much "sulfation" in the battery - bad internal contact - contaminated acid ?.....just curious as to the cause.
You've still got an intermittent connection most likely in a wiring harness junction plug. When the contacts get dirty or corroded there is a high resistance in the connection between the terminals in the plug creating high heat which creates more corrosion and again more heat. Often the connector will be deformed or discolored, but many times they are visually OK, but you can not pull them apart. They have melted together. When the connection gets hot and the metal contacts expand, they lose contact until they cool again and act just like a flasher.
Also check the connections at all of the relays in the electrical box (usually under the hood) where the really big fuses and relays are located. Pull the relays out and look to see if the contacts in the box are distorted or the box melted. Same issue as above.
When you switch to high beams or high heat, you are also switching to a different circuit, different relay, and sometimes even a different ground circuit.
Disregard my advice re: alt. I'm at work and now and looked it up. It may be a Denso or Valeo (French) alt. As everything seems fine the first 9 months of use as indicated it suggest the alternator. The Denso if that is what you have ties back to the cars computer.
It is important to know what alternator you are dealing with...
Be it analog or PWM as loads increase the on/off time to the rotor changes. The rotor is more on than off at higher loads. More info needed.
The french alt is pad mounted the Denso is typical spool foot.
2006 Vue? Non-ecotech engine?
"The pulsing stops...rest of car runs fine. Yeah, "think maybe the pull the fuses one at a time or all at once and then put in one at a time may be the next course."
George, earlier you were saying it does this 'when the car warms up'. Does this car happen to run on the hot side of the gauge, just below overheating?
How about an alternator that is running near or at capacity because of some sort of overload in an engine compartment that's around 240 degrees, tripping some sort of thermal overload?
It seems that after the battery has been topped off from starting and the alternator goes into float, the voltage pulses like the regulator is turning on and off. If you load the system the alternator stays on and the problem disappears. Trying to describe in layman's terms.
I looked at our Saturn records at the shop and we have had two similar problems. Both were related to rebuilt alternators. In each case the issue seemed to be with the regulator, although we don't spend much time researching the failure cause if the electrical system and battery checkout, but the notes did indicate both rebuilt units were Nippon Denso cores.
For both customer we replaced the rebuilt alternators with new dealer units (at our cost) and the problems seemed to have gone away.
One is 12+ months since replacement the other is over two years.
The only difference I can see between your problem and ours is that both rebuilt units completely failed (no output) after around 6 months of service.
I hope this helps a little. - John
A bad battery will cause an alternator to charge at max output and eventually melt the alternator down.
I replaced 3 or 4 alternators on a Subaru once, they were going out about every 6 months or less. I changed the battery and ended that problem.
The pulsing I have no comment for.
My Aerostar had a bad radio buz. Now that it has been mentioned that went away a while back, probably when the alternator went a couple of months ago.
The things I learn from this site!
I had a real bad radio buz on an Astrovan. It was from a poor ground on the exhaust maniflod stud. I also had a problem keeping the battery charged.
Thanks for all the advice.
I've copied it all and sent it to my son so he can continue troubleshooting. This forum is great!
I'll post again when he finds the 'cure'.