History: The car was rebuilt in 1990 and has accumulated about 4100 miles since. A new engine harness was installed and the alternator was rebuilt and worked fine at the that time, but slowly lost it's output. Lights begin to dim, aftermarket radio wanted to turn off at idle and dash lights became non-existant. Radio has a cycling noise in the speakers, even when the car is off.

Two months ago, I replaced the alternator, cleaned the firewall bulkhead connector, the dimmer rheostat and all the dash light grounds. So far, so good. Good lights and amperage but radio still has a cycling noise. I replace the radio two weeks ago with a similar new head unit (CD vs. cassette) and rewire it so that the radio uses both the fusebox battery and accessory leads. Cycling sound goes away. A few blocks from home and the amp gauge pegs. Dead VR.

I replace the VR, check my wiring and the same thing happens again, only this time I notice the the radio went out just before the amps went up. I make the mental connection with the radio and rewired the radio, bypassing the battery connection at the fusebox, like the old radio was wired before. That did the trick. I had a weekend of fun with no problems, but that was shortlived.

Last weekend I went for a drive and within sight of my house, the VR was dead again. This time the 20A fuse (Circuit 4) to the cigarette lighter, int. & ext. lights blew. Replaced the VR, but now I have no output and the gauge isn't lying. Changing the VR does nothing. I've tried two. The replaced fuse is still intact. Alt. works. Open field test works. Voltage is good. VR's grounded.

I've looked everywhere for information on what would kill the voltage regulator. I can't find anything. Does anyone have any insight or suggestions.

Thanks in advance.

 

Wow, that sounds like a pretty odd problem. The alternator has steadily been going downhill since 1990? Other than going over every wire with a factory service manual or taking it to an auto electric shop, you can try running a few extra ground wires, even if it doesn't solve your problem it will increase the electrical systems stability as well as increasing the power output of the engine.

 

I would check the bulkhead wire connections for the alt and the battery- also look under the dash at the amp meter- they have been know to burn/melt like the bulkhead connectors!

John Mac

 

The alternator didn't start acting up until last year and I replaced it this winter. I have checked the bulkhead wires, cleaned them and packed them full of dialectic grease as suggested by Mopar Action. That didn't effect the no-output problem.

Is it your understanding then that only a short could be causing this problem? That's what I assumed when it kept screwing up the first few times, because the VR's worked, something went BUZZZ and then they didn't. It's the blown fuse and "No output at all" that now has me stumped. Someone suggested that the ignition ballast may be the culprit, since the alternator puts out quite nicely when I bypass the VR and perform a full field test. I've never replaced one before. It seems like such a simple device, I don't see how it could break ! I'll replace it this weekend and maybe make the cruise this weekend. Otherwise I'm thinking it's going to be a long, drawn-out process of tracing down an unknown short.

Has anyone installed a dash wiring harness? Does it include the fuse box? I wonder about PAINLESS. I'll check them out.

 

One other thing ....did you make sure that before you installed the new alternator that your battery was at 100% charge. If your battery is not topped off then it can damage a new alternator and cause it to undercharge which defeats the purpose of getting a new one in the first place!

I had a ton of problems with my 71 roadrunner for years with its aging electrical system. The best thing I ever did was contact Ron Francis Wire Works in Chester PA and purchase a complete wiring kit from them. They are sooooooo easy to install and its a step by step process with easy to follow instructions and all the wires are in separate marked bags for each type and area and each and every wire is imprinted every few inches with what it is for.

They're tech support and warranty is top notch and I've even talked with Ron himself about this and that. A truely 1st class product from a 1st class company. And yes their kits come with everything you need to rewire your car. Their fuze boxes are state of the art with new style fuzes and blinkers.

Check'em out at http://www.ronfrancis.com/

 

The battery is less than a year old and fully charged. I have a trickle charger on it for the long periods of time spend hybernating. Which makes sure it's up to the task when I take her out.

Thanks for the advice. I'll check them out.

 

I went through 4 Voltage Regulators before I found one that worked. I guess the reproductions aren't that good.
The guy that did my 73 over also sanded the spot where the VR screws into the firewall If I remember right I believe it needs to be grounded by the screw... When i put the 340 in the guy who was painting painted "EVERYTHING" black so I had to go through and reground things and try not to mess it up.

 

It's almost always the little things that cause the biggest problems. If it were after a period of storage then there is a good chance that a fury little rodent has had fun in it.

 

Oh man ...speaking of that ...this past week I woke my beeper up after a 4 month hibernation. I left some cleaning stuff in her trunk over the winter. Rags, and a cotton bag and some other stuff. My trunk was full of shredded rags, paper towels and little mouse terds! Oh how gross! Well, it was nothing that the ole Sears dry/wet shopvac couldn't handle but the thought of that vermin dining in my baby's trunk was enough to make my skin crawl. I spent that day tracing my entire electrical system to look for knawed wires. Fortunatly the little bastages seemed to confine themselves to the trunk as I could find no telltale signs of them anywhere else in the car.

Lesson learned .....no more mouse food will ever be left in the trunk!

 

So it's not just my bad luck! I used to leave the back door open to my garage so that my dogs could have some shelter during the winter. About 8 years ago, I had a pair of wharf rats invaid my car in the garage while it wasn't used for a few weeks. They munched on carpeting, seat foam, speaker surrounds, radiator hoses and belts. I even found a large dog nylabone in the engine valley under the intake manifold. After 3 boxes of D-Con and a week of waiting, I was following the stench under the crawlspace in the house to the little bastards final resting place. It cost over $1000 to fix the damage. From now on, the windows are always closed.