On my way home tonight, with the miracle of RAIN! in AZ, somehow I blew a fuse that took out the floor lights and radio but not the lighting for the radio. Just before I got home, the headlight got real dim so I turned them off at the mail box. When I tried to turn them back on again, my l'il baby died! I'm assuming that this is because something got wet that shouldn't have. What elements are connected through this fuse so I can try and isolate any issues?

The Batt Fuse only supplies power to the cigarette lighter, radio memory power, courtesty lights, and the convenience center (blue dingy thingy). The Batt Fuse gets it's power directly from Fusible Link A up at the junction box near the battery and C500.

The WDO circuit breaker only powers the electric windows. It gets it's power from Fusible Link A also, but it must go through the ignition switch first since it's only hot in RUN. Not sure why you asked about this circuit though.

The power for the headlights comes from Fusible Link B, which is the other fusible link at the junction box, so I'd start looking for a bad connection there (either loose or corroded).

So you do realize your alternator quit working right?

quote Originally posted by phonedawgz: So you do realize your alternator quit working right?

OK, I'll bite. Among the various possibilities, and given the limited info posted to date, what makes you so sure it's the alternator?

I didn't say the alternator is bad, I said it quit working.

Lost of voltage (headlights got dim) to the point that turning on the headlights killed the engine. He must have been running on battery for some time.

[This message has been edited by phonedawgz (edited 01-29-2011).]

quote Originally posted by phonedawgz: So you do realize your alternator quit working right?

OH, yeah. This has been a nagging headache for a while. BUT, that's why I asked about that circuit BECAUSE with today's rain, I blew THAT fuse. Something that is different with the same result. I've been trying to isolate this issue with the car charging one day and then all of the sudden stop charging. Now that I know what is attached to that circuit, I can see if anything is bare and causing a short

Start with a charged battery, measure DC voltage (with a multimeter) across battery as motor starts. Once the motor is running the voltage should climb to 13+ volts as the alternator charges the battery. If it does not, then go after the field winding and other connections to the alternator. Sounds like water got in somewhere it should not have...

I've checked that. No issues with the connections. I've even re-routed the + cablle to minimize any contact with anhything close to metal. This is also the seconds alternator that is in this. The first one I thought was bad so I poulled it and replaced it with a 100A version. Had the old one tested and it was fine. Thanks for the input DavidM

So far you've stated that the components on the Bat Fuse don't work, that you believe the WDO cct breaker is somehow faulty, that the headlights dimmed before shutting down, you can no longer start it, and now there's a past issue with an intermittent alternator. If there are any other symptoms, now would be a good time to bring them up.

To get meaningful advice, you're going to have to be more specific about your test results and explain exactly what does and doesn't work in your posts.

1. Which connections did you check? Alternator? Junction block?
2. Was it the Bat Fuse that blew, or the WDO circuit breaker that blew?
3. Test the battery like DavidM suggested and post the voltage you're getting with the engine off. If it's below 12V, you need to recharge it. If it's 12V or above, then it may be good, so try cranking the engine. What does it do? Crank or click or nothing?
4. If it starts, test the voltage across the battery terminals again... it should be 13V or more. Is it?
5. With the key in the RUN position, does the Battery light on the dash turn on while the engine is stopped? If not, your charging light is burnt out so you'll need to replace it for your alternator to work.
6. If the charging light turned on with the engine stopped, does it goes out when the engine is running?

Answer each question and the community will be able to help troubleshoot a lot better.

quote Originally posted by Bloozberry: So far you've stated that the components on the Bat Fuse don't work, that you believe the WDO cct breaker is somehow faulty, that the headlights dimmed before shutting down, you can no longer start it, and now there's a past issue with an intermittent alternator. If there are any other symptoms, now would be a good time to bring them up. To get meaningful advice, you're going to have to be more specific about your test results and explain exactly what does and doesn't work in your posts. 1. Which connections did you check? Alternator? Junction block? 2. Was it the Bat Fuse that blew, or the WDO circuit breaker that blew? 3. Test the battery like DavidM suggested and post the voltage you're getting with the engine off. If it's below 12V, you need to recharge it. If it's 12V or above, then it may be good, so try cranking the engine. What does it do? Crank or click or nothing? 4. If it starts, test the voltage across the battery terminals again... it should be 13V or more. Is it? 5. With the key in the RUN position, does the Battery light on the dash turn on while the engine is stopped? If not, your charging light is burnt out so you'll need to replace it for your alternator to work. 6. If the charging light turned on with the engine stopped, does it goes out when the engine is running? Answer each question and the community will be able to help troubleshoot a lot better.

First, let me hand you a nice cup of coffee. Even without caps, I can hear you shouting at your screen

Now, taking each line in turn:
1. Which connections did you check? Alternator? Junction block?

I've checked the connections st the alternator, the starter and the junction block for C500. I've cleaned off any corrosion using a steel wire brush and reconnected each point.

2. Was it the Bat Fuse that blew, or the WDO circuit breaker that blew?

It was the BatWDO fuse in the block. I didn't know there was a separate circuit breaker for the windows...

3. Test the battery like DavidM suggested and post the voltage you're getting with the engine off. If it's below 12V, you need to recharge it. If it's 12V or above, then it may be good, so try cranking the engine. What does it do? Crank or click or nothing?

The voltage at the time it stopped was 10.6 volts. After recharging it, it started right up with a voltage reading of 14.6 across the terminals at the battery.

4. If it starts, test the voltage across the battery terminals again... it should be 13V or more. Is it?

Answered above

5. With the key in the RUN position, does the Battery light on the dash turn on while the engine is stopped? If not, your charging light is burnt out so you'll need to replace it for your alternator to work.

The BAT light in the dash is the first thing I check whenever I start the car. (Believe it or not, I have a printed pre-flight card) If it doesn't light, I don't go anywhere. Also, if the bulb were bad, Item 4 would have showed the voltage to be 12 or lower across the poles.

6. If the charging light turned on with the engine stopped, does it goes out when the engine is running?

During last night's incident, the BAT light in the dash did not come on. This does not ussally happen when I have this charging issue (meaning the light stays off). I have next week off so I will be going over the wiring in the engine compartment more thouroughly to see if there is anything that could be exposed.

------------------
~Trevor
1986 Fiero Sport
"R" Code 'Duke'

You realize the BAT light and the BAT fuse are not related right?

yessir

quote Originally posted by bulldog85043: Even without caps, I can hear you shouting at your screen

Not at all... but I'll take the cup of coffee just the same

I forgot to add that it would be helpful if you stated the year and engine you have. Here's a picture of a typical fusebox from an '86 model... if you could describe the differences in yours it would also be helpful. Notice though, that there are two single bladed slots that are marked BAT, (one on top of the other) at the bottom RH side of the fuse box. These slots are used to power some optional accessories and are fused through the BAT Fuse in addition to the ones I listed above. Does your car have any connectors plugged into either one of these two slots?

Here's a photo of my fuse block. I put in an arrow to the point I'm wondering about:



I'm not sure if the WDO with the white arrow pointing to the metal case is the fuse or a relay that you were speaking of.

Yes, the letters WDO are for the metal thing that the little white arrow points at. That metal thing is the circuit breaker. The BAT Fuse is the one above the word BAT... by the way it should be a 20 amp fuse not a 25 as you have installed. I see that you have no other accessories plugged into the spare BAT outlets so that narrows things down somewhat too.

Please post which engine and year of the car and I'll look back into this tomorrow.

[This message has been edited by Bloozberry (edited 12-17-2010).]

putting a larger fuse in than what is supposed to be there is like flinging lit matches at your interior

quote Originally posted by phonedawgz: putting a larger fuse in than what is supposed to be there is like flinging lit matches at your interior

It was the only one that was available and I needed the lights on. I haven't started the car since...

Bump hoping Blooz has some insight...

So it appears you have at least two distinct problems that are unrelated. The first is your charging issue and the second is a short in the Bat circuit.

For the charging issue, since you've replaced the alternator twice and gotten the same erratic charging, you can probably eliminate the alternator as the source. That leaves the wiring to the field excitation circuit and the main battery charging circuit as potential culprits:

1. For the field excitation, I would start by removing the back of the instrument pod, removing the BATT light bulb and holder, and having a good look at the flexible copper circuit ribbon where the bulb holder makes contact with it. If the copper is dark brown or green, then you should remove the instrument cluster and using a dremel or some emory cloth, gently sand down the contacts on the ribbon for all the bulbs so they make a good solid, resistance-less connection to the bulbs. This is a real possibility since I've had to do this to my '86 when I rebuilt it as well. As mentioned before, the BATT bulb is part of the charging circuit so if it is seeing a bunch of resistance from poor contact patches, it will screw up the charging process. I would also unplug the alternator again and check for any corrosion on the pin with the brown wire, clean it up and reinstall it.

2. For the battery recharging circuit, it's crucial that you physically unscrew the leads at the two terminals at the junction box, clean the eyelets, and reinstall the wires again. Then, unscrew the positive and negative side post terminals on the battery, clean the threads and the underside of the big eyelets of each terminal and reattach them. The most important part is to clean the eyelets since that's what makes the connection to the battery more than anything else. Side post terminals on the Fiero are notorious for corroding because they are under the grills that let water seep into them.

For the blowing BAT Fuse, it's going to be something simple. There's only four items I mentioned before that are on this circuit in your car. Remove the shifter console and follow the orange wire from the cigarette lighter as far as you can. There a possibility it's chafed through near the shifter since that's a moving part in that vicinity. It's unlikely the radio has much to do with it because there's nothing much that moves around it. However the orange wire leading to the courtesy lights are rather loose and can jiggle around and fray or be pinched by the door jamb trim so have a good look at both orange wires to the bulbs. Lastly, it's possible that your blue dingy thingy is giving up the ghost. You could try unplugging it for a week or so and if the fuse doesn't blow again, that may be the problem.

Regardless, you can pretty well rest assured that your two problems aren't related to each other and that it was a coincidence that they happened together. Happy troubleshooting.

When you say you check the BAT light everytime you start the car. So I take it that this has been an ongoing trouble also? The BAT light doesn't always come on?

The alternator problem needs to get fixed but it is seperate from the BAT fuse problem

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Edit
Crap - Blooze beat me to it. Damn you Blooze!

I do agree with everything he says however

[This message has been edited by phonedawgz (edited 12-23-2010).]

Blooz:
Working through your list of possibilites. So far I haven't found anything on the track inside the car but I'm still tearing apart the dash. While cleaning the connections for the j-box, I noticed the large gauge(about 10 or 8 I'd guess) has a hoile in the insulation. After cleaning and reassembly, I covered the hole with electric tape as a temporary measure until I can get the chance to get some new ends and a section of wire from the parts store.

For the back of the IP, I used some 3000 grit WD sandpaper and touched up the connections and the brass ends for both the twity and the contacts inside of it. Replaced with a new bulb. Didn't notice any change in increased lumens (my VOM can measure lumens). My next step ( an the onbe I'm regretting the most) is crawling back under the car so I can recheck the wires for the alternator. I may just follow them up as far as I can and cut/replace with new. Would that be a good idea?

Have found a few things since I last posted:

1. Ground behind dash was pinched in between the bracket and the base of the steering wheel mount: fixed

2. Installed the AUX gauge package and replaced the shell around the upright of the console. Can now directly monitor the Alternator.

3. Had same issue of low voltage. Measured on AUX gauge = ~13V.
Measured across BATT terminals = 12.43V
Edit: Measured at T1 = 12.1V
Measured at T2 = 12.56V
Measured at "Bolt Down" terminal = 12.56V
Measured at small terminal at back of Alt. = 6.7V

Remeasured the same points today and got essentially the same reading everywhere except the T1 position. This time I was able to get a reading from the terminal. I also verified the tension on the pulley and belt.

Thanks for helping me through all of this. This forum rocks!

[This message has been edited by bulldog85043 (edited 01-29-2011).]

Are these voltages with the engine running?

Yes, this is with the engine running

I edited my previous post with an update on the readings...

[This message has been edited by bulldog85043 (edited 01-29-2011).]