Been having a problem with my 99 Passport over the last couple of weeks. First noticed the lights (all light components, i.e. dash lights, clock, etc) flickering or dimming in and out. Figured it was the serpentine belt or a pulley or something.
After peeking around, I noticed that the tensioner pulley was flexing up and down. Too easy, I thought, replace the tensioner assembly and that’ll do it. Well, that didn’t cut it. In the meantime I’ve repleced the belt, as well as the idler pulley which appeared a bit loose. Problem still persists (lights as well as the tensioner flexing up and down)…having extremely limited diagnostic skills, I’m out of thoughts :(.
Any thoughts?? Thanks
take the belt back off,and check for free movement or binding of the alternater pulley,and all other pulleys
A pulley is running off-center, probably due to a worn bearing in one of the accessories. Given the electrical problem you’re having, I suspect the alternator.
Does the dimming change at all when you change the engine speed? Does it happen while the car is sitting still and idling? Or only while moving?
A bad or loose electrical connection somewhere could result in that symptom. If it only happens while driving and is not related to engine speed - I would not be suspecting the alternater or belts etc.
The dimming occurs most prominently while the vehicle is idling. I checked all of the pulleys and only the idler pulley seemed a bit loose. Replaced it and no result. One thing I didn’t mention was that I pulled the fuse to the horn a couple of months back because it was honking at random. One fella I spoke with said he had a similar problem and that this issue (the tensioner problem) could somehow be related to the horn fuse not being in place (he seemed to know what he was talking about, so I just nodded my head in agreement though not really understanding any of his explanation…)So my next course of action is to locate that wire, cut it, throw the fuse in and see if that doest the trick…
Thanks for all the input thus far, please advise with further suggestions!!
when you say the tensioner was flexing up and down too easily; was this while the engine was running? or was it with the engine off, and you pushing on the belt?
have you actually looked (don’t touch) at the pulleys while it’s running?