1972 cutlass battery not charging
#1
1972 cutlass battery not charging
Hi everyone your help would be truly appreciated...
lets see i've gotten a new battery, alternator and voltage regulator. but battery still not charging.Checked wires and they look ok. any suggestions cause im
lets see i've gotten a new battery, alternator and voltage regulator. but battery still not charging.Checked wires and they look ok. any suggestions cause im
#5
#6
Here's a super easy 10 second alternator checkout-With the car running, take a big flatblade screwdriver and touch it to the rear bearing housing on the alternator (the round raised portion in the center of the back side of the alternator). A working alternator is an electromagnet, and there should be a reasonably strong magnetic pull at this bearing, strong enough to pull & hold the screwdriver balde to it. If there is no magnetic pull, the alternator is not charging. This test cannot tell you how ell an alternator is charging (if it is), but it can certainly tell you if it isn't.
#8
If there is no pull, the alternator is not charging. I assume this is an externally regulated alternator with a voltage regulator mounted to the left inner fender? Did they put it on a test stand and run it with a belt driven by an electric motor? I would remove the alternator, take it back to the parts store, & have them test it again, & try the pull test while they're doing it. If there is no pull, have them check another one from stock & do the pull test.
The magnetic pull is a law of physics-if it is charging & generating an electric current, there will be a magnetic pull at the rear bearing of the alternator. Try it on another car if you have one & you'll see what I mean-just be careful, of course, not to ground the electrical post with the wires on it on the back of the alternator (most have a rubber nipple or plastic cap covering it, or at least they did when new). If the alternator tests good on the test stand, verify the wiring is good to the regulator, & that there is no corrosion or excessive dirt at the connections to the regulator. Is there a separate ground wire going to the regulator? If so, make sure it is clean & tight at both ends. Also, have you checked for voltage at the big wire going to the post on the rear of the alternator from the battery? If is is not there, or is low, check this wire carefully-feel it with your fingers along as much of its length as you can. If you feel a "kink" or a soft, mushy, or crusty feeling spot, this could be contributing to your problem-I've seen these wires corrode inside the insulation. Once you get your alternator charging, here's another super simple 10 second electrical diagnostic check that anyone can do. At night, with the engine running & the lights on, connect a good pair of jumper cables from a good ground on the engine to a good grounding point on the firewall or chassis. Did anything change? Did the dash lights get brighter? if they did, then the engine to firewall ground strap is either broken, corroded, loose, has corroded terminals, or is missing altogether (I see this one ALL the time, usually as a result of an engine or trans swap). New straps are cheap & readily available in the "help" section of any good parts store, usually in a red cardboard blister package.
The magnetic pull is a law of physics-if it is charging & generating an electric current, there will be a magnetic pull at the rear bearing of the alternator. Try it on another car if you have one & you'll see what I mean-just be careful, of course, not to ground the electrical post with the wires on it on the back of the alternator (most have a rubber nipple or plastic cap covering it, or at least they did when new). If the alternator tests good on the test stand, verify the wiring is good to the regulator, & that there is no corrosion or excessive dirt at the connections to the regulator. Is there a separate ground wire going to the regulator? If so, make sure it is clean & tight at both ends. Also, have you checked for voltage at the big wire going to the post on the rear of the alternator from the battery? If is is not there, or is low, check this wire carefully-feel it with your fingers along as much of its length as you can. If you feel a "kink" or a soft, mushy, or crusty feeling spot, this could be contributing to your problem-I've seen these wires corrode inside the insulation. Once you get your alternator charging, here's another super simple 10 second electrical diagnostic check that anyone can do. At night, with the engine running & the lights on, connect a good pair of jumper cables from a good ground on the engine to a good grounding point on the firewall or chassis. Did anything change? Did the dash lights get brighter? if they did, then the engine to firewall ground strap is either broken, corroded, loose, has corroded terminals, or is missing altogether (I see this one ALL the time, usually as a result of an engine or trans swap). New straps are cheap & readily available in the "help" section of any good parts store, usually in a red cardboard blister package.
Last edited by a6m5zerosen; November 10th, 2009 at 05:55 PM.
#11
The voltage regulator will be externally the same size whether it is mechanical or solid state. Does it have a removable cover? If so, remove it &
look underneath-if it is a mechanical type there will be a setup very similar to a points-style ignition that opens & closes-that is what regulates the voltage. Caution-disconnect the battery before removing this cover-it is easy to accidentally ground out the regulator. If it is a solid state type, there will be a circuit board with transistors on it. If you have a choice, the solid state is a much more reliable, trouble free unit with no moving parts & no contact points to wear out.
look underneath-if it is a mechanical type there will be a setup very similar to a points-style ignition that opens & closes-that is what regulates the voltage. Caution-disconnect the battery before removing this cover-it is easy to accidentally ground out the regulator. If it is a solid state type, there will be a circuit board with transistors on it. If you have a choice, the solid state is a much more reliable, trouble free unit with no moving parts & no contact points to wear out.
#12
something i noticed today was that the last owner has the alternator ground connecting to aftermarket gauges (temp,oil,amp).i put an extra ground from alternator ground to chassis just in case but nothing..the regulator has a metal braided strip from one screw going to the engine thats ground, right? one more thing i can think of doing is getting new regulator connector wires.ones i have are old and might be corroded.also before i changed the regulator the gen light would light up when car was on not to bright.when installed new regulator light can only be seen at night thats how dim it is.
#14
I believe you may have multiple issues. Do you have a factory (not an auto parts store manual diagram) color coded wire diagram for this car? If not, perhaps someone on this forum can scan the relevant sections & email it to you, or post on the forum. Once you have this, check the wire colors & connectors. Payspecial attention to anything that looks altered or non-stock-look for cheap auto parts store splices or scotch-locks (blue plastic rectangular foldover splices), wires twisted together & taped, etc. Lots of time you see this under the dash (as a result of a bad stero install), near the fuse box (as a result of a bad accessory installation-guages, lights, etc), in the trunk (as a result of a bad trailer light or speaker wiring attempt), & under the hood (lots of reasons-hooking up aftermarket guages, tach, ignition upgrades, fog lights, etc. Check out that alternator again, too-I think you've got a bad unit. Take it to a different store, or have it checked by a different employee.
#16
im going to take alternator to another shop to get tested just in case.and i got myself a factory electrical diagram.going check all wires to make sure there not altered or damaged...yeah the red light works with key in run position.
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