i need some help with a little(hopefully) electrical problem. i have a 69 malibu and recently the stereo started to shut off then turn right back on. After about two week i noticed that the junction box that is located in front of the battery near the headlight was melted. i bought a new junction box and even put an in-line 30 amp fuse from the wire that comes off the battery to the junctio box. Well needless to say this didnt fix my problem. The stereo is still cutting off but now its not cutting back on and the turn signals are not functional now. Im thinkin i have a bare wire or a bad ground. Any ideas on where to start or if im on the right track. Also what would it cost to replace the entire wiring in the car. alot of the old wires are brittle and wondering if i should just replace everything. im kinda short on $$$ so i was hoping to put this option off for a while thou.

That junction block should have a fusible link between it and the battery. power for the entire car goes through that wire. See pic

http://www.chevelles.com/showroom/data/500/medium/Original_Chevy_system.jpg

I would check the charging system, if the voltage is to high the radio may be shutting off to protect itself. To check for proper voltage start car and run at a fast idle and check voltage at battery, it should be between 14-14.5 volts.

Ok i checked with a digital volt meter and i was at 14-14.5 at high idle, UNTIL i turned on the headlights. then i would drop to around 8-9 and my stereo would cut off. I figured maybe my alternator was bad so i took it out and had it bench tested. it showed everything was Good. Now my battery went dead so i bought a new one of those. Only problem is now with new battery is its not charging. At fast idle im only showing 12 volts and then it slowly drops after 15-20 minutes. Does this sound like the voltage regulator? everything i read on here so far it seems like your voltage reads high when it goes bad and thats not my case. Any more suggestions?

Charging sysem is not charging. Could be the voltage regulator (is it externally regulated?)

yes its still external. so u think i should try a voltage regulator? Also my idiot light doesnt work. the last guy cut the wire on it. im also not that good with the voltage meter as to do all the test on the voltage regulator like ive read on one of the post.

yes its still external. so u think i should try a voltage regulator? Are you sure its externally regulated? To tell the difference see this post, w/pics
http://www.chevelles.com/forums/showthread.php?t=105661
Personally I would convert to a internally regulated alternator if you still have the externally regulated one.


Also my idiot light doesnt work. the last guy cut the wire on it. im also not that good with the voltage meter as to do all the test on the voltage regulator like ive read on one of the post.
Where was it cut?

It is external voltage regulator and i replaced it today. the voltage at the battery is now showing 13.5 at high idle and with the lights and heater on it shows about 12.5 which is higher than before but still nothing close to 14-14.5. any suggestions? Also the wire to the generator idiot light was cut up near the firewall i think. if u can tell me what color it is i cant tell for sure.

It is external voltage regulator and i replaced it today. the voltage at the battery is now showing 13.5 at high idle and with the lights and heater on it shows about 12.5 which is higher than before but still nothing close to 14-14.5. any suggestions?
Test voltage at the battery (with it fully charged, should be 12.5) with the car off, what is your reading? Test another car at fast idle and off (with a known good charging system) what is your reading? Your meter could be out of calibration.


Also the wire to the generator idiot light was cut up near the firewall i think. if u can tell me what color it is i cant tell for sure. Wire for the GEN light is a 16g brown, it goes from the firewall bulkhead to terminal 4 at the voltage regulator. (trace the wire from the VR to firewall bulkhead) To test it, disconnect VR plug, with the key on it should have 12 volts, if it does ground the wire and GEN light should come on. If it has power and GEN light doesn't light, bulb is burned out. (power would be coming from bypass wire under dash).

well i replaced the alternator (with new voltage regulator and battery in place) this morning and low and behold everything is working right again. i guess the guy at auto zone didnt know what he was doing on the bench test. Thanks for your replies and help. This site is very informative and im learning alot about working and troubleshooting.

well i replaced the alternator (with new voltage regulator and battery in place) this morning and low and behold everything is working right again. i guess the guy at auto zone didnt know what he was doing on the bench test.
:D :D :D

Thanks for your replies and help. This site is very informative and im learning alot about working and troubleshooting.

:hurray: :hurray: :hurray:

Awesome. I'm having that exact same problem with my stereo. I wonder if that is what causes my car to idle rough after I've been running it for a while when it's hot. Any idea on that too? It acts likes it wants to die when I'm sitting in traffic for a long time. Too much consumption and not enough charging?

yea i had that problem also. i would start with a digital meter and take the readings like UNDEE70ss recomended. Unfortanatley for me i think my voltage regulator stuck wide open and fried everything, so i had to replace battery, alternator and regulator. hopefully u will only have to replace one of them. good luck.

Did that problem with the car wanting to die stop when you replaced the alternator?

yes, but i replaced the battery and voltage regulator also. have u checked ur alternator to make sure its charging properly. ur probably just running off ur battery.

Good deal. I've been wondering why my car would do that when it's hot. One more question for you. Did the car ever hesitate when you accelerated hard? I'm thinking that is being caused by this now. The car demands a lot of juice to get going, but if the alternator isn't charging properly, it's going to stutter before supply meets demand. Please let me know when you can. I'm going to try to take care of this today before I have to do heavy holiday driving.

Honestly i dont remember it hesitating. Im no expert but it seems that would be more mechanical(engine). Did u find the post of what all your readings should be with the volt meter. if not ill try to copy and paste it here for u. let me know how u come out.

well im back and the problem started again. i noticed the other day it was getting hard to turn over again so i checked my readings for ****s and giggles. i am only at 13.5 at high idle and i know thats not right. i also keep blowing the fusible link behind the battery at the junction box. Any ideas? Dont know if this has anything to do with it but my distributor is rusty as hell also, but i read on the msd site this is typical of the msd distributors.

i also keep blowing the fusible link behind the battery at the junction box. Any ideas? Dont know if this has anything to do with it but my distributor is rusty as hell also, but i read on the msd site this is typical of the msd distributors.It takes a pretty big short to be blowing the fusible link. Most of the time the short will be in the main wiring, or the unfused circiuts. the unfused circuits are power to the fusebox, power to the ignition switch (which also goes to dizzy) and the headlights. Since you were having issues with the headlights....
Ok i checked with a digital volt meter and i was at 14-14.5 at high idle, UNTIL i turned on the headlights. then i would drop to around 8-9 and my stereo would cut off.
I would first look for you short here.

dont know if this matters or not but the fusible link(which is temporarily a fuse holder with 30 amp fuse) will not blow until i turn the engine off then i cant resart car until i replace the fuse. im doing this temperarily till i find the problem so i dont keep putting in fusible links. Any help on how i look for this short would also be appreciated.