HELP! Newb! Radio(aftermarket deck) dies when put in reverse/signal/brake. Signals seem slow and delayed as of recent. Just switched to Optima yellow top. Anyone have similar issues? Switched battery because the old one was not keeping charge over winter early spring . Used alternator tester and got Just below low end reading When testing at new optima battery. Possibly alternator ? Car runs and starts amazing with new battery.
HELP! Newb! Radio dies when put in reverse/signal/brake. Signals seem slow and delayed as of recent
- Thread starter Salvatore
- Start date
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Are you running the factory power wire to the new head unit? If so, that’s part of your problem, those wires were barely designed for 3-5 amp draws, a lot of newer head units are drawing 5-10 amps constant. More if it’s a dual DIN
mechanicmark
Well-Known Member
Did you change ground (neg.) battery cable with battery? Still have a solid body ground?
Demonic
Well-Known Member
Put a multimeter on the battery and tell us the idle voltage.
There is a big wire directly from battery to starter so no surprise it works well. Everything else is on a much smaller and more complicated supply. Voltage drop is pretty common in these older vehicles. Original equipment work continue to work although not great ( slow turn signals, etc..). Modern electronics like your stereo often require a full 12 volts. Factory 18AWG wire should be sufficient. Where is your voltage drop? Good hunting
Just swapped battery no changes to cables
No issues for 2 years prior on normal lead battery until it started dying this winter.
I didn’t build the car but it looks like this might be the issue although it was fine for 2 years prior on other battery. Could it be my alternator
At idle I’m at 12 v when I test the alternator it shows 13 In a red range which says no bad on my alternator/battery tester. Could the alternator do this . Is there also some kind of voltage regulator ?
yes, there is an external voltage reg
I’m driving a 73 dart sport with a built 340, aftermarket deck , all the wiring looks stock tho . But why am I getting the issue now . Could the alternator be doing this Alternatively Could the voltage Regulator be comprised of I’m still goo driving under normal RPM. It seems extra power draw example signals reverse lights is why u want to say it happens when out in reverse gear as well
67Dart273
Well-Known Member
Lets start with "to where"/ what circuit is the radio wired? And have you measured voltage to the radio when under load with brakes/ signals/ etc causing the problem
If the thing is tapped off some existing fuse circuit it could be as simple as a "going bad" fuse, or corroded fuse clips in the fuse panel.
"We" have no idea how this might be wired up
If the thing is tapped off some existing fuse circuit it could be as simple as a "going bad" fuse, or corroded fuse clips in the fuse panel.
"We" have no idea how this might be wired up
I figured if a fuse popped it would be totally dead I’ll have to go over the fuses. I’ll try to trace the wiring. When in check my alternator/supply it’s 13 v just under the good range Could this be the issue ? Don’t want to buy a new alternator if not necessary. Would a bad alternator at 13 v be doing the described. I’m trying to figure out the alternator wiring but the wiring looks tiny. I’ll snap a picture for the team!
I’m just checking alternator supply at the battery with a battery/alt checker. I have a multimeter but don’t know where to begin with the 2 tiny wires on opposite side. One blue one green are these supply !? They have plastic clips that mate to the alternator. Can’t see a thick power supply cable.
67Dart273
Well-Known Member
13 is for sure low BUT it could be several things besides the alternator or the regulator
FIRST make sure the battery is good. CHARGE it with a good charger and test or have it LOAD TESTED. It could have a problem, or just be 'down.'
Next make SURE the belt is tight and not slipping. Glazing, smell can be a clue. With the battery charged and normal and the engine warm (the regulator is voltage/ temperature compensated) and with the idle jacked up to simulate low to medium cruise (fast idle) check battery voltage first with loads off, and again with lights, heater, stereo, all accessoris running. Compare voltage at the battery POS post, at the starter relay "big stud", at the alternator output stud, and anywhere you can 'get to' on the interior such as
Big red wire feeding the igntion switch connector BOT SIDES of connector (coming out of steering column)
Probe various fuses for any voltage variation
The next issue which "is popular" with these cars is VOLTAGE DROP in various parts of the wiring harness. This is in part caused by too small wire to start with, plus addition of modern high power devices, plus 50 or so years of corrosion. 'Popular' problems include fuse link and connections, terminals through the bulkhead, terminals at and internally in the ammeter, fuse clip corrosion, and in rare cases but "has and does" happen, failure of the factory welded splice. This is a large splice up inside the under dash harness, where the black wire from the alternator, the ammeter, the headlight power, the power to the ignition switch, and power to the 'hot' buss in the fuse panel all come together.
FIRST make sure the battery is good. CHARGE it with a good charger and test or have it LOAD TESTED. It could have a problem, or just be 'down.'
Next make SURE the belt is tight and not slipping. Glazing, smell can be a clue. With the battery charged and normal and the engine warm (the regulator is voltage/ temperature compensated) and with the idle jacked up to simulate low to medium cruise (fast idle) check battery voltage first with loads off, and again with lights, heater, stereo, all accessoris running. Compare voltage at the battery POS post, at the starter relay "big stud", at the alternator output stud, and anywhere you can 'get to' on the interior such as
Big red wire feeding the igntion switch connector BOT SIDES of connector (coming out of steering column)
Probe various fuses for any voltage variation
The next issue which "is popular" with these cars is VOLTAGE DROP in various parts of the wiring harness. This is in part caused by too small wire to start with, plus addition of modern high power devices, plus 50 or so years of corrosion. 'Popular' problems include fuse link and connections, terminals through the bulkhead, terminals at and internally in the ammeter, fuse clip corrosion, and in rare cases but "has and does" happen, failure of the factory welded splice. This is a large splice up inside the under dash harness, where the black wire from the alternator, the ammeter, the headlight power, the power to the ignition switch, and power to the 'hot' buss in the fuse panel all come together.
Show a photo or the name and model of this battery/alt checker.
How was it connected and at what rpm when checking the alt?
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It’s just your average universal unit. This one is branded SCHUMACHER ive seen them branded by many different names All look the same internally. I’ve bought and used one before on one of my past vehicles. Oldest car I’ve owned before this was my 1987 Iroc Z Which is fuel injected, so I’m new to this old Carb and old mopar stuff, and I’m no mechanic. Im a machinist/cad/cam guy, but I do my own oil changes and have done some brake jobs, and have taken apart a lot of industrial robots and machines. Easier to rip apart other people’s things and not worry as much if it’s going back together properly/timely haha aka at work. This is my first...classic car..1973 I just turned 30 years old... I told I’m going to have a lot of fun. And A LoT of Headaches with the Dart.
Picture posted . It has bulky clamps so you connect it at the battery and it shows the running volt and when you hold the button for a quick second, i believe it completes a circuit and pulls current to test the supply volts. Take a quick Rough reading this way I was suggested if I couldn’t figure out the alternator. All my checks were at idle around 1000-1200 rpm
I believe this might be the case or some other stock power supply but it ran like this for years before me owning and almost 2 years of my ownership no problems.
67Dart273
Well-Known Member
Consider rereading my post. You can't "get much" by just taking a reading. As I mentioned there are several MAJOR power junctions that could be the problem on top of "the usual" wiring problems further down the line. It might help to read the article on ammeters. This explains why the problem exists. And it really is several problems, because it can exist in several components.
Also the basic diagram there gives an idea of the major power flow this article:
Catalog
Follow along on this simplified diagram
Main power from the BATTERY to the starter relay BIG STUD. From there the FUSE LINK goes to and through the BULKHEAD CONNECTOR (RED) and to the AMMETER--through the AMMETER--and out on BLACK---and from there to the WELDED SPLICE
Each one of those points is subject to DETERIORATION AND FAILURE
As I mentioned earlier it can be further down the line. If you are using the fuse panel to supply power to the stereo, just something as simple as a corroded wire terminal or fuse clip can denegrate 'the whole deal'
POWER or more correctly CURRENT FLOW is what causes voltage drop. If you measure power at whatever fuse is supplying a load, and that load is NOT POWERED, then there is NO current flow and you will NOT see the problem.
You have to "crack the books" get a diagram, maybe draw part of it out and notate every wire, every connector, fuse, EVERY point in the circuit path that is in that wire and then check the ones that you can get to easier, and work from there.
Also the basic diagram there gives an idea of the major power flow this article:
Catalog
Follow along on this simplified diagram
Main power from the BATTERY to the starter relay BIG STUD. From there the FUSE LINK goes to and through the BULKHEAD CONNECTOR (RED) and to the AMMETER--through the AMMETER--and out on BLACK---and from there to the WELDED SPLICE
Each one of those points is subject to DETERIORATION AND FAILURE
As I mentioned earlier it can be further down the line. If you are using the fuse panel to supply power to the stereo, just something as simple as a corroded wire terminal or fuse clip can denegrate 'the whole deal'
POWER or more correctly CURRENT FLOW is what causes voltage drop. If you measure power at whatever fuse is supplying a load, and that load is NOT POWERED, then there is NO current flow and you will NOT see the problem.
You have to "crack the books" get a diagram, maybe draw part of it out and notate every wire, every connector, fuse, EVERY point in the circuit path that is in that wire and then check the ones that you can get to easier, and work from there.
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67Dart273
Well-Known Member
Your load tester may not be enough to show up a battery problem. You may have to research a parts store or other shop in your area who has one and knows how to use it.
Example........they usually can measure upwards of 300-500A, this one is claimed to be 800
Example........they usually can measure upwards of 300-500A, this one is claimed to be 800
The most complete set of MTSC up to the mid '70s is collected here:
Master Technician Service Conference - Chrysler's Training for Mechanics
Mymopar has some more of the later ones in a different format (pdfs instead images). They also have some digitized Service manuals for download. if you want bette quality or paper, then Bishko is a decent retailer.
OK. Lets look at the instructions. https://www.batterychargers.com/sites/default/files/manuals/0099001450-R2.pdf
It's basically a voltmeter with a fixed resistance that can be turned on to load the battery.
There's usually a big difference in power generation between idle (650 to 950 on a few cars) and 1250 rpm. The instructions for that tester say 1200 to 1500 rpm in general. So you can see its not just Chrysler's alternators. I'll come back to this.
I beleive you. So the question is whether its battery, alternator, or a wiring issue. Wiring issues could be a poor connection from the alternator feed choking the flow of higher currents, or a something that is causing additional current draw. One cause of additional current draw would be a run down battery. So that is definately the first test to test. The question is not whether the battery has lots of power, but whether its fully charged. A crude check is after starting the car to check the ammeter for when its done charging.
Alternator:
Alternators are very rpm dependent.
Here's the max output specs for a GM 12Si with the engine rpm for my jeep (which uses this alternator).
All alternators have max output curves something like this.
Power is P = IV so take 667 engine rpm, the '94 amp' alternator can produce up to 50 amps x 12 v = 60 Watts.
When tested at higher voltage, the current will be lower.
So.
Make sure the belt is snug.
Make sure the battery is done recharging. (use the car's ammeter to check)
Then start putting load on it per the instructions.
Note that they do not suggest using the tester's internal load. They suggest turning on the lights and heater fan.
Yes. And one way to narrow it down is observe if it is just when going to reverse, or when any additional electrical demand is made at low rpm.
Shut off the stereo. Put foot on brake and turn on headlights, then add the heater fan.
Do the lights get dimmer with more load?
Does the ammeter go from no charge to discharge?
The alternator could have one of the three field windings or one of the three stator windings out of commission.
Those 'squareback' alternators are pretty easy to open up and check most components.
Yesterday I tried tightening the belt by adjusting the alternator, may have got it a bit tighter. But then I actually had the car die on me when I went to put it in reverse and turn around in a parking lot. Battery was too dead to start back up. Got a friend to charge me up and made it home no problem. I want to pinpoint this to the alternator by diagnosing it also came in at 10 volts when checking . I can get one from the Local parts source.
I believe mine is a 2-groove pulley I want to say 60amps ? Does anyone know what choice is correct. 65 single groove, 60amp 2-groove, 114 2 groove. Pictures supplied
I believe mine is a 2-groove pulley I want to say 60amps ? Does anyone know what choice is correct. 65 single groove, 60amp 2-groove, 114 2 groove. Pictures supplied
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