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One of three things, bad battery, bad alternator or an open circuit staying on after you shut the car off.
Haven't had to do this in long time, but Auto parts stores should be able to check for a good battery.
Quick check to determine if the alternator is changing the battery. Disconnect the alternator while engine is running, battery should be enough to keep the engine engine running.
I went through this a few years ago. Have the alternator tested. Most parts places can do this.
A few years ago, my very old alternator finally died. I went to the local Autozone and bought a new one. A few days later my new battery was dead. I went back to the Autozone and had them test their alternator. It was bad. So were the 2 other new ones that they had in stock. They wound up calling around other stores and it took 2 trys before they found a store were they actually had one that passed their test.
Have the alternator tested. Most parts places can do this.
A few years ago, my very old alternator finally died. I went to the local Autozone and bought a new one. A few days later my new battery was dead. I went back to the Autozone and had them test their alternator. It was bad. So were the 2 other new ones that they had in stock.
I agree, get the alternator tested. Many moons ago I worked at various auto parts stores and we would test alternators before the customers left the store due to the high out-of-the-box failure rate.
Check battery voltage, fully charged it should be 12.6v. The .6 is very important. Next check the voltage at the battery with the engine running, it should be 13.9-14.2v.
I consider those bare minimums. 12.8 for a resting battery and 14.4 for a properly charging alternator.
Well when I flip my key switch to on position just for the radio the volt meter reads just 11.5 even when I crank up the volt meter is just barely at 12
Charge battery full before making tests. If you are taking alternator back where you bought it for testing, have them test your battery also. If you have a volt meter we can help you here on the forum.
Update : I just tested the battery and alternator with volt meter…..battery had 10.36 cranked the car up and still didn’t change.
so I touched the neg volt side to the neg battery side then touched the positive to alternated casing and it read 0.1, which my understanding that’s not good for having a good alternator.
My question and the mystery is what is causing the alternator to not work which lead to battery not staying charged. Even when it’s running and lights are on radio on the voltage drops way too low…..I know it is suppose to drop but not that low
Any help with be appreciated in the interim I will go and get a new battery and alternator but man…. There is something causing this to happen
Has this problem just started with the new components? If it has, one of them is suspect. Have the alternator and the battery load tested.
Disconnect your battery cables and check them for resistance. Also the wiring from alternator to the junction block/horn relay, and the pigtail from battery positive terminal to the junction block.
If you don't have a factory Olds chassis service manual you need one. It has color wiring diagrams that show how the alternator supplies power to the battery.
My question and the mystery is what is causing the alternator to not work which lead to battery not staying charged. Even when it’s running and lights are on radio on the voltage drops way too low…..I know it is suppose to drop but not that low
No mystery at all. Alternator isn't working.
With engine running it should be putting out minimum 14 volts, reading at both the alternator post and the battery positive terminal. If not, the thing isn't working. Get it tested, if it tests bad, replace it and make the parts store test the new one before you walk out with it.
With engine running it should be putting out minimum 14 volts, reading at both the alternator post and the battery positive terminal. If not, the thing isn't working. Get it tested, if it tests bad, replace it and make the parts store test the new one before you walk out with it.
so alternator isn’t working sure but something is causing it not to work this will be the third alternator and battery change so something gotta cause it
Rocket raider ……it is the third time this sequence has occurred……something is causing the alternator to go bad which lead to battery not working wires to junction no or relay all appear to be connected unless these relay boxes go bad …..I don’t know
Is it the original 1969, externally regulated unit? If so, you may be overlooking the regulator on the firewall. Replace that with a new solid state unit. I believe there is a way to jump the regulator pins into triggering the alternator to charge, but I'm not sure. I usually just convert to an internal regulated unit.
Yes its all original.....heads have been changed only it has #69(1970) heads instead of original #5(1968/69). There is a voltage regulator on firewall and that too has been changed out.
The GM 12SI alternator is the later style with an internal voltage regulator. If you decide to go that route you have to bypass the voltage regulator on the firewall, or the two regulators will counteract each other.
At one time AutoZone had the correct plug for your alternator. If they don't try NAPA. Not good having those wires where they can short against the alternator case.
I wondered about this, but you say the car has a voltage regulator on the firewall and your alternator has the right plug I I opening for that setup. 1969 442s had internal regulator alternators that used a different - - plug and no regulator on the firewall. Is your 69 a 442?
Look close at the heavy gauge red wire that goes to the yellow splice connector. That's the main power feed for the car and how the juice gets back to the battery to charge it. If that yellow connector splice is weak or broken internally it will affect battery charging and about everything else electrical on the car.
There's also a fusible link on a couple of those wires that affect things too. That pop you heard on the no start thread could possibly have been a fuse link blowing.
Wow ...............thanks ....looks like I just got to unravel the tape to find the fusable link...btw I took the alternator in to replace and it tested good .....they gave me another one anyway tested that one as well it was positive. So Ive gotta find the culprit
The heavy gauge red wire goes to a black wire connected to the battery cable which goes to the starter main side
That's how it should be. Original positive battery cable had a long pigtail from battery terminal over to the junction block. As battery cables got replaced, the new parts store cables came with a short pigtail and butt splice connector.
Some years negative battery cables came with a pigtail too. It went to a chassis sheetmetal ground, sometimes on a fender, sometimes on the radiator core support. Those can wreak havoc too if not connected correctly.
If your horn works ok I don't see any need to get that new relay OR has. Wouldn't hurt to take all the wires off the junction block post and wire brush them to clean off 50-some years of grunge while you're into it. Battery cable ends too. Sometimes electrical problems are as simple as a dirty connection. Ask any Ford owner! 🙂
Yep yep good post.....thanks for the awareness...my horn does work I was just going to take all those wires from that old and make new/clean wire as well
I'll hedge a bet to suggest the OEM fusible link is as depicted in the image below. The fusible link should be black wire off the horn relay junction block>then into the fusible link> with a red wire from the fusible link. Hard to see (kinda dirty).
Note above I said "should". They changed numerous wiring locations and evidently some of the wiring colors during the 1968-1970 years.
NOTE: The 1968 fusible link wire remains red>red. https://classicoldsmobile.com/forums...iagram-102204/
I can't find a 1969 wiring diagram.
NOTE: The 1971 fusible link wire is black>red. https://classicoldsmobile.com/forums...-v-8-a-146374/
Argh! It will be clearly identified in a wiring diagram from 1969 none-the-less.
Just to highlight the wiring (from my 71 CS) which may assist you. Not certain if it will address your issue, but an image can help represent what you're looking for. I labeled it distribution block (incorrectly) it's name is actually a junction block (horn relay).
We're gonna suss out this problem and get you going. All of us want to see you enjoy your car and none of us want to see you broke on the side of the road or worse see your Oldsmobile light off due to an electrical issue.
No need to be afraid of electrical work. Just understand it and respect it.
October 9th, 2021 | 05:38 PM
