Ok.....to start out. My nephews 89RS had headlight problems. While driving the headlights would cut off. After a few minutes they would come back on. So I had him come over and we replaced the Dimmer switch and headlight switch. It seemed to good after that but a few days later he said his voltage gage was reading low. He took it to AZ and since it was under warranty....they replaced it even though it passed the tests. Turns out he got a bad replacement! He brought it over again and I discovered one of the fusible links from the gang post by the battery had broke in 2. So just as a diagnostic type set up.....I put in a regular inline fuse (30 amp). It didnt fix the low voltage so I knew it was a bad alternator. He took it back and it failed. They replaced it.....again....and all seemed fine. He got home...put in the new alternator....and took it for a test drive. Everything was good so he took it out again and tried it with everything turned on. He said the voltage dropped to 10. When he got back to the house the fuse we installed was blown.
Hes bringing it over tomorrow. Is there anything I should look for besides a stripped wire or short? Where should I start? Im thinking that fusible link is for the headlights so unless anybody knows anything about this or has a better idea....Illl be starting there. Thanks for the help.

 

Just as you said the headlights have a fusible link (Fusible Link A) so get that replaced. If your blowing it then you may have a short somewhere in the headlight wiring. Either to another wire or to metal. For the low voltage problem usually its the voltage regulator. Just because yall have gotten a couple "new" alternators does not mean your not getting crap parts. Especially if they are from AZ and/or rebuilt. I would look into upgrading all your main power/ground wires. The alternator to battery wire, ground from batter to block and your body ground wires. Go with as big as you can 0/1 gauge.

Have you checked the voltage at the battery while the car is running? Or just looking at the gauge? I would check it at the battery just to see if you are getting good voltage or not. Also have you had the battery tested? Maybe is due to be replaced..

 

.....ouch that pink kills the eyes.

Sometimes you get a bad batch of parts.
Not kidding, my mother has an 02 ford explorer, and we have had to take back 3 different "remanufactured" alternators after a week of use due to a squeaking.

Does the car ever have problems starting due to low charge? Where are you reading the voltage from? The only accurate way to be reading voltage is from the battery, not the instrument cluster.
Try swapping relays around for the headlamps with something else, see if that fixes it. I've seen those short/stuck before and cause a large parasitic drain.

Don't replace the fusible link, keep the fuse holder/fuse thing you put in there, as it's far more convenient to replace. You can even buy a circuit breaker (looks like a metal housing fuse), that clicks when its overloaded, then once it cools off, it resets on it's own. They use them in power seats. Convenient for diagnostic purposes.

 

Ok, checked everything out real good. Found out its not the headlight fusible link thats blowing out. Its the alternator link. All the wires looked good. The grounds are solid. They wires that I could see looked good. I put a 50 amp big fuse in instead of the 30 and it blew. Its ok when we turn on the lights, then defrost, but then wipers....it blows. Could it be something in the starter? Im to the point where were going to have to pull the wiring harness and check every inch of wire . How many amps is that supposed to be pulling? The Haynes manual is confusing. It has 2 diagrams. One dont even show a fusible link and the other that does only says 14 gauge. Swapped out all the relays with another Parts camaro we had and no luck. The fan wires and every wire I could see looked good. Not a faded or scratched wire anywhere. Where the wires run by the block seemed good even. Any clues where to start or what to do next besides pulling the entire wire harness? Could it be something in the dash even? HELP! lol
Thanks again guys

 

By the way....the car starts and runs fine until you start putting a real load on it. I told him just try not to drive at night and dont use your wipers and lights at the same time. lol

 

Just a word of advice. NEVER put in a larger fuse than what is designed to be there. You run the risk of burning up your wiring. The fuse is there to blow so your wiring doesnt... lol

 

Yeah I understand about the fuses....I wish something would just go out so I knew what the cause was lol

 

So after today... Im still stuck on this I started out by installing a 30 amp fuse in place of the Fusible Link. The alternator looks good voltage output wise. I put a meter on it and got 14.??? We then took it for a ride...slowly one at a time added power accessories....1 Headlights... 2 defroster on high heat. Still looked good. Meter in car said 13 on the nose. No fluctuation. I then put the wipers on....still good. Then I put the rear defroster on and it blew the fuse I put in. The Volt gauge drops to 8 when this fuse blows. That leads me to start at the alternator....So I put a new fuse in (40 amp this time) and now its still not working....Volt gauge is still reading 8....so the alternators power isnt getting to the next point....which is what Im looking for now.

I checked the relays after running through 3 main power lines that all looked good. I noticed the one relay. I believe its the fuel pump relay because the car wont start without it hooked up. I noticed what looked like burn. Im attaching some pics. It had a slight burnt smell to it but very slight. I also noticed that the black looks like some electrical sealant type soap. Could this be the problem maybe? Any input or ideas are welcome. Who knows.....the problem could be in the rear defroster ???!!!! How would I clean up the male part and wiring????? Should I get a new pump relay? It seems to work good as far as starting the car. Could it be the cause and still do its job??