help with a draw.

[ooimpalaoo]

ok so I'm looking for a draw took my battery out overnight. removed my neg lead started pulling fuses one by one. then checking for spark after each one. still nothing.....what do i do next? removed my positive from distributor. nothing....could it be my light switch failing? I have heard of this . people talking about it grading back . what do you think I should do? What's next? thanx .

[harpo231]

Are you sayin battery draining ? need symptoms

[suburban99]

Use a VOM meter on DC Amps. Disconnect negative terminal and tape it to the red VOM lead, then connect the black VOM lead to the terminal...should not be more than 50MA on most vehicles. Once you determine amp draw pull fuses one by one till it improves, then troubleshoot that circuit. Probably interior lights, dome lights, or dash lights.

[bigrigpardo]

Could be a failing battery but if not check the voltage reg to see if it's sticking. Or the alt itself.

[demian5]

Originally Posted by suburban99

Use a VOM meter on DC Amps. Disconnect negative terminal and tape it to the red VOM lead, then connect the black VOM lead to the terminal...should not be more than 50MA on most vehicles.

This is good, but from your original post I'm thinking you are not too keen on diagnosing. Lets take it down a level. You can connect a regular car light bulb between the disconnected negative cable and the battery (or use a test light) and disconnect things till the light goes out. Remember that if you have a door switch and dome light, to pull the dome light bulb so it's not keeping the light on at the battery - indicating a load.

[ooimpalaoo]

so the spark is the same as the light ...the light I couldn't find.....ok so after finding the light did it all again just to make myself happy and the same thing . light stayed on. should I start to remove starter wire's, alt, what am I missing . I don't have a glove box light.

[70 shorty]

What they were saying above, is pull one fuse at a time. If the light goes out, you've found your problem circuit. If the light doesn't go out, reinstall the fuse and pull the next one and so on and so on.

[ooimpalaoo]

that is what im saying too. and im saying that i am and have been doing this and still the light remains on. i know this old trick. im at a loss for what to start to pull next. ? any help would be great

[ratty69]

Try disconnecting the alternator. If one of the diodes fails it will still charge, but at a reduced rate of around 13V. It will also backfeed and drain your battery...

You can confirm it by checking for continuity from the alternator output stud to the case - you should have none ( open circuit ).

[Steeveedee]

Originally Posted by ratty69

Try disconnecting the alternator. If one of the diodes fails it will still charge, but at a reduced rate of around 13V. It will also backfeed and drain your battery...

You can confirm it by checking for continuity from the alternator output stud to the case - you should have none ( open circuit ).

This is a good thing to try. Btw, do not pull a battery cable to check, if it is running, or it can lead to the problem ratty mentioned, all on its own.

[ooimpalaoo]

ok so i did what ratty69 said (started with the two plug wires) not the main red power wire and the light went out .....there she is the dirty draw that has had me opening my hood for a year to remove my batt cable. so what are these wires? are they what you where thinking or where you thinking more about the main power lead? is this the diode? where do these 2 plug go (do) this should help a few people. thanx for all of this. as soon as that light went out my 69c10 smiled and so did i.

[ooimpalaoo]

ok so i did what ratty69 said (started with the two plug wires) not the main red power wire and the light went out .....there she is the dirty draw that has had me opening my hood for a year to remove my batt cable. so what are these wires? are they what you where thinking or where you thinking more about the main power lead? is this the diode? where do these 2 plug go (do) this should help a few people. thanx for all of this. as soon as that light went out my 69c10 smiled and so did i.

[harpo231]

One to battery ,, one to switch I believe

[Steeveedee]

Diodes are inside the alternator, and are pressed in. If you've isolated it that far, a rebuilt alternator would be the easy solution. Or you could rebuild it yourself, if you want.

[ooimpalaoo]

but since I only took the plug out and the light went out. and one side of the plug goes to the power on the alt. does the other not to to a light?

[ooimpalaoo]

like he said one to switch. so is the switch grounding? because I left the main power line on

[ratty69]

Those two wires that plug into the alternator go to the voltage regulator. The regulator is located on the rad support l/h side near the horn. ( This is assuming you have the original setup still. )

If the draw went away when you pulled the plug out of the alternator, then next is to unplug the regulator. Looks like bigrigpardo might have nailed it in post #4.

[ooimpalaoo]

so looking online I see that you can delete the voltage regulator....any reason I shouldn't???? from what I saw they said to get a 78_80 alt ...whats the difference mine still has the same wire's. I think they are talking about how it mounts . anyways. can I delete this thing?

[bigrigpardo]

yes well it all depends on if you want to keep your truck all original or not. if not then yes a later model internally regulated alternator. usually called a chevy 1 wire will do the trick. just unhook the stock regulator on the rad support as it wont be needed bolt the new alt in place run a thick 10 or 12 gauge wire from the stud on the alt to the positive battery cable and one short wire from the stud on the alt to one of the two terminals on the alt. I forget which one. google chevy 1 wire alt hook up and it will show you.

[VetteVet]

This is how simple it is to convert to the internally regulated alternator.
You can use the 10 SI alternator or better yet one like I pictured off a mid eighties GM truck or car called a 12 SI.

You will need to get the small plug that plugs into the side of the alternator off a car in the junkyard, or you can buy the plug at autozone for a few bucks.



Then just hook the wires as shown.

This is the normal three wire setup which I recommend. If you get a one-wire alternator then all you have to do is mount it, and connect the battery wire to the back, nothing else needs to be done.





You have a 12 gauge red wire on the old alternator and it will work if you don't have a lot of auxiliary stuff. Just reconnect it to the back of the new alternator and plug in the plug after you have connected the wires to the regulator plug. You won't need the small blue and white wires with the old plug.

[Steeveedee]

Can he put the one-wire alternator on and still expect the C/D gauge to work properly? I have a cold and had to take some medication which makes me drowsy; else I'd go find the answer myself.

[ooimpalaoo]

I'm going to take pics of my truck tomorrow so you guys can see what I'm dealing with. I don't know why my alt now won't work. pics to come . 69gmc 910 with a inline 250 hei install power steering power brakes , 5 bolt swap and disk brake front upgrade.. long tube headers. air bagged all 4 corners...5 speed tranny.. and some 2bbl carb with a sight bowl that I can't identify.. yes I know my vacuum line to my booster isn't on so don't all get in line to start on me I'm fixing one thing at a time . pics tomorrow oh I forgot drop spindles a and c notch.

[VetteVet]

Originally Posted by Steeveedee

Can he put the one-wire alternator on and still expect the C/D gauge to work properly? I have a cold and had to take some medication which makes me drowsy; else I'd go find the answer myself.

\

Yes I've posted on this many times. As long as he runs the power wire to the same spot it goes to originally (the soldered junction). Most guys just run the power wire to the positive battery post or to the starter cable terminal on the solenoid.

The battery gauge wires are connected at the fender terminal on the passenger side and to the soldered junction. There is a battery charging wire connected there that runs back to the fender terminal and connects to the fusible link which is connected to the positive battery terminal. So this wire runs between the alternator charging wire on one end and the battery positive on the other end.

This wire is called the shunt and it senses the voltage between the battery and the alternator. When the voltage is higher at the alternator end, the gauge shows charging, but when the voltage is higher at the battery end it senses that the alternator is not charging and the gauge will show discharge.

If the alternator power wire is re-routed directly to the battery end, it bypasses the Shunt and the gauge cannot sense the voltage between the battery and the alternator and it will not work.

This is kinda oversimplified but it is basically how it works.

Here's a diagram showing the Shunt.



Here's the junction on the right fender showing the connection of the Shunt, the fusible link to the battery positive and the battery gauge wire with the four amp fuse inline to the battery gauge. The other wire is connected to the alternator junction on the other end of the shunt wire.

[VetteVet]

I forgot to mention that the one-wire alternator won't charge unless you rev the engine on start-up and it isn't very good at compensating for voltage drop downstream from the alternator and you might not get full voltage for the lights or cooling fans. It seems to work OK for a lot of folks if they don't have a lot of high draw loads in the circuits.

[ooimpalaoo]

ok here is my truck and the wire plug that comes from my alt. can this alt work?? or do i need to swap it out for the delete?? not letting me post pics something about a security token