cascading electrical failure.

In case you don't know what that means, one electrical system after another seems to be having problems on my car.

It all started about a year ago when I fried my alternator. I tried putting a 200amp unit in to see if it would run cooler and keep itself alive. WRONG MOVE! All that did was cook one of the fusible links, there's two behind the battery on a '95. You lose one and it won't charge, you lose the other and it over charges. I replaced the fusible link, several times, until I had a manual I didn't know what size to throw in there, so not wanting to blow the harness I put in smaller ones till I knew which size was correct.

Systems that have been affected in order of distruption:
Cigarette lighter - I used that to power an air pump at the autocrosses
rear backup lights
side marker lights
driver's side headlight motor
driver's side headlight

All fuses are AOK

With all the C4's I've read about spontaneously combusting, I have the feeling I've got a harness fire in there , so I really need to find out what's going on. I've hate to take it to a dealer but I might have to.

 

200 amp?!

18 wheeler's use less then that

what kind of voltage were you putting out?

 

I see no connection between the higher rated alternator and all your other problems EXCEPT blowing out the alternator fusible link! Each problem can be tackled one at a time and if you are willing to trace wires through the harness, then a dealer needn't get involved. The alternator puts out a constant 14.7 volts, identical to the original alternator, so you cannot blame it for electrical problems.
The cigar lighter runs off the 15 amp ctsy/clk fuse but the lighter socket is really only meant to deliver about 5-7 amps, but, I doubt your air pump drew much more than this. The headlight motor runs off 3 relays and these will need to be checked along with the motor ground and the quality of the motor socket. The headlight also has a socket and a frame ground and these should be checked. Backup lights use a switch on the transmission which usually fails, also, these lights have lamps that fail, socket corrosion and socket ground to the frame should be checked. Same for the side marker.
You should check with a voltmeter, or a 12v trouble test lamp, the path current flows to the devices that don't work, from the source to the device. For instance, with the headlight switch on, check for 12v on the output of the switch, then on the output of the dimmer switch, then on the headlamp socket. Then check for a good ground connection on the black wire on the headlamp socket and the headlamp itself. Hope this helps, you will need the electrical diagnosis service manual which shows and explains each circuit and describes where each connector and wire color is.

 

you live in the land of salt and rain.

I am betting you have some corroded grounds. There are less than 27 grounds on these damned things!!!!

What I would do is this, remove the battery, inner and outer fender and the battery tray. Check all the links, the junction boxes and grounds. Many are right there. They are also prone to damage by weather.

 

My volts start off at 14.7 then dip down to 14.3, unless the radiator fans kick in, then it dips down to 12.8, for about a second, then it shoots back up.

BTW I took the 200amp unit out a while back, and had the original alternator rebuilt and installed.

I'm checking them out one by one, this is my daily driver so it kinda hard, I really hope it not something central.

BTW2 It has more problems during 'spirited driving' as the alternator is spinning faster.

 

the problem/RPM relationship makes me think the killer alternator has a questionable voltage regulator.

I have some experience with hi-power alternators, they are troublesome at best, and questionably unrealible at worst.

They are rather popular in the car audio, at the same time, they are returned as faulty more often than not.

I would love to put an amp meter on the alternator and test the output as the temperature rises. A couple months ago, I replaced my dead alternator, the new one died within 2 days! However, it was ok, I drove it, then it went wacky, and the volts went up. I waited for it to cool, then removed it and took it to the parts shop, where it passed the testing machine. The next morn, I put it back in, and drove it. I didn't get very far, when the voltage spiked again. This time, I removed it, took it back, put it back on the tester, this time, it failed. Big time.

This was a basic, over the counter reman. I cannot believe that the hi-power folks are doing any more than the reman folks. Except they are using hotter voltage regulators and diodes.

 

pretty hard to ground to fiberglass.

its true though, just look in wiring diagrams and you'll see how many circuits ground to the same location. on my 84, @30 courtesy light circuits go to one common ground.

 

same here. i read the tech article on this site about swappin the old 84 si-17 alternator for a delco 321-368. it didnt work at all. the pulley was spaced to far out like it was gonna pull the belt off the steering pulley, and the harness adapter i got wouldnt make it connect right, so it wouldnt charge. i would recommend an oem ac-delco reman. they seem to be done very well.

 

Affected how?
These voltage readings, is this w/ the dash meter, or a handheld meter?
The voltage dip when the fan turns on is normal. DC motors have large start current draws. Checking and cleaning GNDs is a good start.

 

Completely dead circuit

Some cheeful new though! Now that I've had a chance to look at it, the headlight just lost it's lowbeam, the highbeam is AOK, since I replaced it's twin this summer it's probably just the light.

This was a Texas (southern) car. I've only driven it in the winter the last couple of years.