Fix one thing......something else breaks.......


went to work today...everything was fine...had to run out a couple hrs later, and my charging light comes on. belt & tensioner are new, so what's left??? I assume it's my alternator. Try to make it to my buddy's midas shop so he can change it. He has it tested to make sure the alternator is bad......they said it was.

put the new(rebuilt) unit in. all seems fine. i drive about 1/4 mile, look down, and my charging light is on. I go back, they put a digital meter on it, it says alt. problem. they remove & replace it(returned one didn't show bad when they tested it). light goes off, meter shows there is still a problem. they search for awhile, fiddle around...then all seems fine. i go home, then run out.

truck runs fine, no lights.......life is good.....NOT!!!!!!!

on my way home, radio light starts to dim. turn on lights.....watch my volt guage drop like a rock. could the alternator going bad screw up something else on it's way out??? maybe a relay or a fuse??? guys at midas did check some fuses and found nothing. i'm a self employed contractor, and NEED my truck to eat....lol

any help you guys can give me w/b greatly appreciated.


OB

'98 f-150 screw, xlt, 4x4 4.6

 

Battery? connection at starter? connection at relay on firewall?relay?

 

meter shows batt is fine

starter was replaced a month or 2 ago

connection @ relay on firewall seems intact.

not sure about the relay itself......could the alt. dying make the relay go bad???

 

disconnect the negative side of battery while engine running if it dies the relay is not allowing the circuit to be completed....how old is the battery? anything beyond 3 years warrents suspision

 

ok tex...will try that in the morning. not sure it could be a batt problem.....i thought once a vehicle is running, the alternator kept it running. since my truck dies once the charge gets too low, there must be a charging sys problem......right????

if it turns out to be the relay, where am i gonna find one??? prob a dealer only item?? or maybe the boneyard......????? or is it not worth chancing it with a used one??

 

i dont know about that relay thing. the only thing that goes through that is the starter. the rest are just connected to the same post on the relay. i would say check the big a## fuse just below it. put meter on batt. wiggle large cables on both sides and watch that meter. when those fuse's blow they can make contact off and on. and confuse you when checking them. also try wiggle fuse 19 i think,its in fuse box under dash. that is for charge light but i have seen funnier things happen. they are know for getting bad connection. pretty much wiggle test. if it comes and goes you should be able to find it that way. good luck


wayne

 

think i found the problem.....after putting yet another alt in. Had the old one tested @ autozone...they said it was junk. brought it back to where it came from, they said it was fine. ppl @ autozone weren't grounding it properly doing the bench test.
guess it is mandatory that the alt be put in the vehicle with a FULLY charged battery. don't know if late model cars have alt's with some kind of memory or what. anyway, i think the first 2 alts put in, were put in on a drained battery, then put on a charger to charge & eventually start the truck. somehow this process was screwing with the installation of the alt.
anyway, i put the 3rd one in myself, autozone fully recharged my battery, and everything seems fine(fingers ARE crossed!!!!).
thanx for the posts and ideas guys.

 

One thing I would NEVER do on these late model vehicle is to disconnect the battery cable while the vehicle is running. This could short out the computer. Just my 2cent

 

i agree smokey.....was just makin a point......that the alt keeps the vehicle running from an electrical aspect. in other words...while the vehicle is running, the battery is hardly used.