Hello! I'm having an ongoing electrical mystery with my Chrysler 300. 440 4bbl, new alternator, and the wiring is completely stock and appears to be in good shape. A few weeks ago, I was having a difficult time getting the headlights to work. I replaced 2 headlamps that were out, but then kept on blowing the lamps, and it seemed to be cured by re-using the old dimmer switch. Once I got all 4 headlights working with the old switch, all seemed well, and I drove the car for several weeks without incident. Fast forward to yesterday. I was trying to get the dash lights to work. Checked a few connections under the dash, still nothing. I started the car, then turned on the headlights and got nothing. Dead. I hit the dimmer switch to turn on the brights, and 3 of the 4 lights came on. I reved the engine...my buddy who was standing in front of the car said the the lights got so bright they turned blue, then they blew. I checked the tail lights. All dead. Pulled the bulbs. 2 of them appear to have popped. I figured that I had a bad voltage regulator, so I replaced it. I replaced one tail light to see what would happen, and it lasted for all of 10 seconds, then blew. I put a voltage meter on the headlight socket. I was getting around 15.5 volts at idle, but when I reved the engine, the volts jumped to 40+! When this was happening, the aftermarket voltmeter in the car showed a slight discharge, around 11.5V when the car was running, and the ammeter did not work at all. It seemed like the voltage regulator was not working. I'd had some problems with the engine compartment wiring harness at the bulkhead connector; they were badly corroded, and I've cleaned them several times. I unplugged all 3, cleaned them again, reconnected them, started the car up, and the voltmeter read 14 volts at idle, and about 14.8 when reved. The factory ammeter also started working, showing a full charge that slowly tapered back to center as the car ran, ALTHOUGH both the voltmeter and the ammeter seemed to pulse back and forth for a few minutes. The car seemed fine. I figured that it was a bad connection, so I put the car away for the day. Fast forward to today. Crank it up, turn on the headlights, and the one new sealed beam lit up super bright, and then turned blue and burned out when I reved the engine. Back to f*cking square 1. It seems as if the voltage regulator is working intermittently. Could a bad connection at the bulkhead connector cause the voltage regulator to malfunction? I don't know the amp rating for the new alternator to PO installed. The guy at NAPA said that the car could have 2 different voltage regulators. One for 34 or 46 amp alternator (not the EXACT numbers, but close), and one for a 60amp alternator. I matched the new voltage regulator to the one that was in the car, which was the lower amp one. Could having a mismatched voltage regulator and alternator cause the voltage regulator to operate intermittently? The car is out of the HAMB friendly age range, but it's still in the 60s. (1968). I apologize for that, but I'm posting here because of the AWESOME knowledge base here, and honestly, 'cause I don't know what else to do. This problem may help someone who may have the same problem with a HAMB friendly car. I'm pulling my hair out with this one and getting really frustrated. Thank you. Chris Monroe, CT
no idea on your issue, but in the 70s I worked for Dodge and one older guy said some 60s Chryslers or mopars, used super high voltage under the dash. I don't trust my memory from 40 years ago, but I think it was 110 volts? Could be BS, maybe someone can add to this story. Hard to believe, unless some sort of transformer? I thought he said it was for gauges, not sure. If it is true, maybe it back fed to the lighting circuits? ,
Well, at this point I'd replace the voltage regulator and definitely have the alternator checked. Could a poor connection at a bulkhead connection be part of the problem? Very likely; most alternators use a 'sensing circuit' that's connected at a 'main' power point, generally under the dash. The idea is to check voltage at this point and 'adjust' the alternator output to maintain voltage at that point so all the electrical is supplied with enough voltage. If this circuit has a large voltage drop due to a poor connection, the regulator will see that as low voltage and boost output voltage trying to maintain voltage. Note that the actual alternator output comes in via a different wire, so if the 'sensed' voltage is real low, the regulator could increase voltage to the point you have. Re-clean those connections, but use some DeOxit on the connections (get it online, electronics suppliers, or guitar stores). If you don't have a wiring diagram for this car, get one; it will make troubleshooting easier.
Good info here on your bulkhead connector issue and good Mopar alternator info. http://www.allpar.com/history/mopar/electrical.html This page has a newer car as the subject of the question but the question and answer match up with you problem http://answers.edmunds.com/question...ler-300M-Alternator-battery-short-161699.aspx Basically he is saying that you have a broken/bad connection between the alternator and the battery causing the alternator to have max output.
The regulator must be as big as the alternator or bigger. Someone may have put in a heavy duty alternator. If you replace the regulator and use the bigger one, it will do no harm even if you have the smaller alternator. But do check which alternator you have. The alternator should not "run wild" even with a blown regulator. I would carefully check the alternator, the wiring, and the regulator or have it checked by an auto electric shop. You definitely have an alternator putting out too much voltage. This can only be caused by too much power being fed to the field, in other words, bad reg, bad wiring, or possibly a bad alternator. F&J is thinking about the "electroluminescent" dash light system used by Chrysler in the sixties. It worked off a 400 volt power supply transformer under the dash. Has nothing to do with the alternator.
I would check the wiring carefully and put on a new regulator. If that does not fix it, take the alternator in and have it rebuilt.
I would check the ammeter very carefully, they are known to have problems...when they go "open circuit", the charging system goes haywire. The same can be said of the bulkhead connector, as mentioned
There is only 12-15 volts (no more then the alternator can put out) under the dash on Mopar cars. There are a lot of places that can have crappy connections that can and will create a lot of heat, but the voltage is limited to what the alt or battery can produce. If you still have the factory voltage gauge in the dash, replace it or eliminate it. The connections at the back of the gauge were difficult to keep clean and tight, and would begin to arch. That gauge was the cause of many of the 60s & early 70s Mopars electrical issues. All the voltage in the car goes through that gauge. The second issue with the 60s & 70s Chrysler was the bulk head connector, which you have already experienced. This is another place where all the voltage passes through. To make things worse, all the separate circuits pass close to each other, bad corrosion can allow voltage to stray to unwanted places. Pull it completely apart, clean each side of all the wire connectors, then find a way to protect the connections. The next thing I would do is check the wire connections on the headlight switch. Any burnt connectors need to be replaced. you may also want to look at the wiring harness that lays across the motor. it may have gotten hot and started melting wires together. I believe you are experiencing several different issues taking place at the same time, rather then one big issue causing all the problems. With the headlights being bright then turning blue before burning out indicates to me the headlights are shorting the charging system to max output, and the two systems were not directly connected from the factory. I've given you 4 places to start looking. and one, or all four can cause your problems. Unfortunately, there are many more places that can cause problems. The wiring, connections, and switches have had 47 years to deteriorate. Given the issues you are having, it may be time to replace the wiring on the car to eliminate the bulkhead connector, and the voltage gauge, and maybe put the headlights on a relay. There are aftermarket wiring kits that would resolve your problems. Gene
To all - THANK YOU for the input. At the moment, it's Friday early evening, I have a few drinks in me, and I'm in no mood to crawl under the hood or dash, but I PROMISE I will early next week. I will follow everyone's advice and see what I can find. HOWEVER! - I had a thought, please tell me what you think. I looked at a schematic of the wiring I found online a few days ago. It seems as if the circuit for the VR has a wire from the alternator to the field terminal of the VR, and the other end of the VR goes to the ignition switch, please correct me if I'm wrong. My ignition switch is very loose. I can insert the key and turn it, but it doesn't always "catch". Sometimes I have to push it in/wiggle it, in order to make it catch. Could I have a grounding issue in the ignition switch? Would grounding the ignition end of the VR in the ignition switch cause it to stop working and send full, unregulated voltage to the lights? Just a thought.... Thanks, and I'll dive into in early next week. Chris
I doubt it's grounding issue, but if that's the 'sense' wire (and I suspect it is) and it has a poor connection, that could be your problem.
If I am thinking correct the field term on the alt to VR is the wire you would ground to full field the alt to check output. So if that wire is grounding out on engine or body it could be causing your problem.
Not trying to be a smart ass,but I would also check in a Mopar forum,more than likely someone there has had this problem.;moreso than here on the HAMB..
Wbrw32 - Agreed. I have posts on 2 different Mopar boards, but I couldn't ignore the technical brainpower of the HAMB. Custom/Hot Rod guys are the best ones to solve out of the ordinary problems 'cause when you start putting together different parts from old vehicles, you learn how to solve those out of the ordinary problems like this one. Anyway, been doing a LOT of reading and research, and need to check that I understand the charging system correctly...please tell me if I am wrong... As I understand the charging system, current flows FROM the ignition switch, through the VR, and into the field, and through to ground. The VR regulator senses the draw from the electrical system and the battery, and adjusts the current going to the field according to the draw, thus changing/adjusting the output of the alternator to match the demands of the system. Is that correct? Another question - From what I've read, early (round back, which is what I have) Chrysler alternators came with 3 different amerage outputs, mid 30s, mid 40s, and 60. How do I find the amperage output of my alternator? I want to make sure that I have the correct VR in place. Thanks... Chris
Ok, I think I have it figured out... I pulled the alternator to get it tested, just to rule it out. I took it to an old-time auto electric shop, where they owner mounted the alternator on his testing machine while I watched. "It's fine", he said. I then told him what was going on...unregulated output at the batt terminal of the alternator, 11.9 volts at the battery, and a car full of blown bulbs. He told me that I have a textbook example of a broken connection between the batt terminal of the alternator and the battery. "You alternator is working fine, but it has all this voltage with no place to go. It's passing through the bulkhead connector to the factory weld splice that feeds it to the lights, ignition, etc., but from there, it's not making it to the battery". Smart guy. He told me that I could simply run a feed from the batt terminal of the alternator to, you guessed it, the battery, with an appropriately rated fusible link. That would, of course, bypass the ammeter, but it would fix the problem. I went back to my shop, reinstalled the alternator, disconnected the battery, and used my jump pack and a test light to check continuity of the wires leading up and away from the factory ammeter. Alternator to engine side bulk head connector - check Interior side bulk head connector - check Power wire to the ammeter - check Output terminal of the ammeter - NOTHING Output terminal on the engine side of the bulkhead connector - check Current through the fusible link to the starter relay - check. SO...it appears as if I have a bad ammeter, ALTHOUGH I have seen the ammeter work SOMETIMES. I know that the ammeter is a weak point in all early Chryslers, and there's typically problems with the shunt between the terminals. I'd like to keep the factory ammeter if I can. Am I better off just bypassing the ammeter and installing an aftermarket one? Is there a way to fix the ammeter? Any other advice before I tear the instrument cluster out? Thank you. Chris
I'm sure there's an instrument shop that could repair your ammeter, but I'd personally have it converted to a voltmeter if going to that much trouble. Or you could simply bypass the stock ammeter and install an aftermarket voltmeter.
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