charging system?

I have an 88 Scottsdale 350 and last night when I parked it everything was fine except for a slight whinning noise when the lights were on but went away when the lights went off, I went to work this afternoon and and the batttery was dead. I replaced the battery and when I got to work (7 miles away) I tried starting it and it started right up. I tried it again at 9 tonight and the battery was dead. I forgot to mention that when I got to work, I left the truck running and dissconnected the positive cable and it stalled immediately. After jumping it, it started right up and drove home with lights, heater, stereo and dome lights and everything seemed fine. my Alt guage read just to the right of the middle but I noticed my battery light was on but really faint, the more throttle I gave it the brighter it got. When I turned everything off the light went very dim if on at all. :banghead: No lights are on, not even the glove box and it still drains. Any help would be greatly appreciated

It sounds like your have a short in one of your circuits. To test the circuits take a test light, disconnect the negative battery cable, attach the test light clamp to battery neg. terminal and the probe end to the neg. cable. Make sure the ignition is off and all doors are closed. If the test light is illuminated, you have a short that is draining your battery. Start removing the fuses one at a time until the light goes out. You have at least found the circuit affecting your problem. Make sure that the doors are closed each time you check the light as the courtesy light being on will illuminated the test light. Check both fuse boxes, inside cab and under hood.

I have an 88 Scottsdale 350 and last night when I parked it everything was fine except for a slight whining noise when the lights were on but went away when the lights went off, I went to work this afternoon and and the battery was dead. I replaced the battery and when I got to work (7 miles away) I tried starting it and it started right up. I tried it again at 9 tonight and the battery was dead. I forgot to mention that when I got to work, I left the truck running and disconnected the positive cable and it stalled immediately. After jumping it, it started right up and drove home with lights, heater, stereo and dome lights and everything seemed fine. my Alt gauge read just to the right of the middle but I noticed my battery light was on but really faint, the more throttle I gave it the brighter it got. When I turned everything off the light went very dim if on at all. :banghead: No lights are on, not even the glove box and it still drains. Any help would be greatly appreciated


Disconnecting the battery when it is running is a No-No- No.:no no:
You may have blown a alt diode or regulator.

Is there battery voltage on the big wire to alternator?

Most parts places will give you a free charging system check with alt on the truck.
Have it tested on truck and see if it is charging good.
Does the alt light come on bright key on?

Dim feed back on alt light with it running is normal but not a bright light.
Also the alt will whine some when charging.

Disconnecting the battery when it is running is a No-No- No.:no no:
You may have blown a alt diode or regulator.

Is there battery voltage on the big wire to alternator?

Most parts places will give you a free charging system check with alt on the truck.
Have it tested on truck and see if it is charging good.
Does the alt light come on bright key on?

Dim feed back on alt light with it running is normal but not a bright light.
Also the alt will whine some when charging.

The alt light is bright with the key on. I dissconnected the negetive cable and started checking for shorts. I did have a very dim light for the courtesy light. Not sure why, I never use it and the bed light never did work as long as I owned the truck. possibly the problem or one of? I'll call around to see who does tests. Do you know if the alt from a 78 chevy p/u will fit? aside from the pully needing to be swapped? my other truck also has a 350 but its regular fan belt, not a serpentene belt

Get it tested before throwing parts at it.
Good Luck

I put my test light on the red wire to the alt and theres definately power there. I could'nt take a reading with my volt meter cause my battery is dead in that too UGH!! what is it with batteries with me????? heh

ok, now even with a fully charged battery it don't turn over. I pulled out the starter and it looks like its gotten hot from the exhaust and I can't get it to do anything.. Is a starter from a 78 Chevy 350 the same as my 88? I just want to make sure before I tried. I have enough problems

Proper testing before throwing parts at it.

Proper testing before throwing parts at it.


I recommend that you bring to a repair shop with a reputation for repairing electrical problems....

Unless YOU have the knowledge and equiptment needed to diagnose, this is best.

See if the alternator is puttin' out as it should. Test the alternator field output terminal for 15 - 16V first, then test down-wire for continued current, and check wiring too...

Maybe also check starting wiring:

If (and ONLY IF) the battery is fully charged, then you need to test cables. Test the negative to the frame, test for 12V at the solenoid input from battery, test coming OUT of solenoid (TO starter (with key ON)), and test input 12V going into starter.

If no voltage coming OUT of solenoid WITH KEY ON, solenoid is bad.