PLS. REFRESH ME...ALT WIRING...LIGHTS DIMMING

Hello all,I posted a while back and can't seem to find my posted question. I'm wondering how I stop the dimming of lights at low idle? I believe there was a wiring harness to buy that helps this.Also is there a bigger alt.(with part no.) that I can put on the 440 block?When I bought the stroker it came with a single wire alt. but I don't know how to rewire the existing to use it.

You can check the Moparts Tech Archive. Lots of information on the subject, plus you can Google search about the topic as well.

Oftentimes, the Headlight Switch in our old cars is an antique and rather corroded, a weak link. Replacement switches are available and relatively cheap.

Beyond that, rewiring using relays so as to not send the heavy headlight current through the headlight switch and firewall connection, is a way to get rid of the dimming-at-idle and overall brightness issues.

Upgrading the wiring to the alternator ( along with circuit protection, fuses, fuseable-link, etc) can help the entire system as well.

if you have a less than std dia crank pulley (7.25") going to a 7.25 will speed up the alt (& pump which is generally OK) & may or may not require a smaller pump pulley depending on the current ones' dia so a std (7.25) crank pulley will fit which will speed up the pump even more. I'd clean ALL connections/wiring. The easiest would be to relay the headlight directly to the alt which works very well (keeps the ammeter honest also) & there's no downsides to this (maintain good relays/wiring/terminals/connections). As said there are other alt options that charge better at idle.

On my Cuda, I eliminated the dimming and reduced firewall harness load by adding a bypass wire between the Alternator and Starter Relay stud and I added hidden relays under the battery to power all of the lights.

As it was pointed out, the power has to run through a crap-ton of connections before it ever gets to the lights so there is plenty of opportunity for voltage reduction.

Power leaves the Alternator then crosses through a bulkhead connection to get to weld at the ammeter. From there it goes to the light switch then into the foot dimmer then through another bulkhead harness to get to the lights. I think I left out a connection but you get the idea. Increasing the (idle) output of your Alternator with a different ALT one or smaller pulley will give you more power at low-RPMs but if your wiring system already has high resistance from older connections you will put further strain on those connections.

Relays near the lights will help you get their feed closer to the battery which helps but in my opinion it is not enough. Even if you connect the lights directly to the battery, the power still has come from the Alt which means you are sending the power through four firewall connectors and across the weld near the ammeter.

Installing relays and adding an Alternator bypass wire makes sure the load stays on the engine side of the firewall and takes considerable strain off the old connections in our cars.

Your alt. should be putting out 14.2 volts at idle. If you have one diode out it will cause this problem.. What is you idle rpm? should be 750..

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Your alt. should be putting out 14.2 volts at idle. If you have one diode out it will cause this problem.. What is you idle rpm? should be 750..

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Start with the alternator, check it at idle.

I did the Mad bypass and installed relays for the headlights and even for the AC clutch and my lights still dimmed at idle.
Took a closer look at the alternator and found it low at idle, as soon as I'd rev it some the voltage would come up.

Replaced the alternator(which may have been defective, stocker 20+ years old) with a powermaster and now I'm good at the lowest idle. It put's out 14.3 volts at a low idle and 14.8-15.1 volts at speed. My stock electronic ignition has never been happier. It's been 10 years on the first one on my 71 and 4 years on the second one on my 74 so far, both work great.

Instead of changing my amp meter to volts(not easy) i stuck this cheap volt gauge in my cig lighter.(easy)
It'll works good and I can see the voltage drop from the battery to the cig lighter. I put a good DVM on the battery and checked the voltage both places and the plug in DVM is accurate. When I'm not wanting to see it I toss it in the console.