Dim headlights at idle....simple fix?

[easy610]

my 1972 'Cuda is pretty much bone stock.  All lights dim substantially at idle.  Is ther a simple fix?  More powerful alternator? 

Not worried about going non-stock.  This is a VERY clean car, but I drive her so I'm not freaking out about OEM looking parts. I am mildly handy, but not very electrically proficient!

Thanks VERY much for any help!

[Chryco Psycho]

this is typical of all Mopars they discharge at idle , a different make of Alt may help

[GoodysGotaCuda]

First off is I would check voltage at the headlight connector itself when they get dim. Compare it to the battery voltage, if its off (...it will be) two good options to do.

     1) Delete the ammeter and factory/weak bulkhead connections. (RedLineGaugeWorks can convert your factory Ammeter to a Volt Gauge keeping
     the stock look)

     http://www.madelectrical.com/electricaltech/amp-gauges.shtml

     2) Put the headlights on relays. This keeps the current from having to travel from your 30+ year old connections and switches.

     here is how i did mine
     http://www.goodysgotacuda.com/Headlights.html

     inspiration
     http://www.madelectrical.com/electricaltech/brighter-headlights.shtml


Now that may not 100% cure ALL dimming at idle. Finding a smaller alternator pulley would also help that out making it spin faster. I've yet to mess with that one. Where abouts are you located? There may be a local member than can help with the electrical if you are a little shakey on the subject. 

 

[easy610]

SE Michigan....Plymouth to be exact.

Thanks to all thus far...

[6packCuda]

     2) Put the headlights on relays. This keeps the current from having to travel from your 30+ year old connections and switches.

  I did that on mine a while back and it made a huge difference. It's a pretty simple conversion.

[Robb]

     2) Put the headlights on relays. This keeps the current from having to travel from your 30+ year old connections and switches.

   

This is the way to go.    Then upgrade to bigger alt if you can still justify it.

[easy610]

Painless headlight relay en route....will post results when installed this weekend.

[troutstreamnm]

easy,
Can you post the part number and details for the Painless relay kit?  Thanks

[hooD]

Painless headlight relay en route....will post results when installed this weekend.

If you do this, let me know how easy it was. 

[Chryco Psycho]

it is very easy to do , you need a pair of 30 Amp relays , a fusable link to go from the starter realy terminal to the #30 post on the realys & hook the high & low beam wires to the headlights to the opposite terminal 85 I think then hook the high & low beam wires to 86 one on each relay & grond the opposite terminals 87 I think , you need 2 relays & 8 insulated female spade crimp lugs , a fusable link & large ring lug , 2 -3 feet of 12 guage wire ,& 2-4 feet of 18 guage wire to grond to the headlight ground bolt near the battery & a ring terminal for those wires as well

[ntstlgl1970]

this is typical of all Mopars they discharge at idle , a different make of Alt may help

I have an upgraded "100 amp" chrysler alternator with the small pulley, larger ga stator wiring and rotor windings and it only puts out 19A (measured with a Sun VAT-40) at idle (850 RPM) and 82A max at about 2300 RPM with the output cable (new 6ga) connected directly to the battery. If you don't have any add on electric items like a electric fan, fuel pump, big stereo, hi wattage headlamps, then that might be enough. If you need more power, try converting to a later Denso alternator (like goody did) if you want to make the dimming problem go away. Newer style alternators can put out 50A or more at idle.

[GoodysGotaCuda]

my lights dip a little bit at idle even still, however i do run an electric fuel pump, big electric fan, msd, stereo, very bright 90watt low beams, etc. However overall its much better than factory

[Aussie Challenger]

  Relays is the only way to go, my Challenger now has over 13vlts at headlights where it had around 5vlts. The main benifit is that the relays take all the load current off of the 30 year old head light switch. Goody had a thread with pictures, did a real neat job and they were basically hidden too. The realys only cost a few bucks and the wire and terminals are very cheap.

[422STROKER]

Relays were simple to do and I get 13.8V at idle to my headlights now.  Even with the HB's on it's good and then the foglamps too.  It drops to about 13.0 at idle with everything running(LB's,HB's,FL's,Heater,Ignition,Stereo w/amp, and Wipers.)  This is with a Stock 60A A/C alternator.

Tom

Clean all your grounds first.  Then clean all your connections(Bulkhead, and Lights), also tighten your Ammeter connections or bypass it as Goody and others have highlighted.  Disconnect the Battery before cleaning the connections.

[GoodysGotaCuda]

  Relays is the only way to go, my Challenger now has over 13vlts at headlights where it had around 5vlts. The main benifit is that the relays take all the load current off of the 30 year old head light switch. Goody had a thread with pictures, did a real neat job and they were basically hidden too. The realys only cost a few bucks and the wire and terminals are very cheap.

Here is my route that i posted up earlier, its still up there!
http://www.goodysgotacuda.com/Headlights.html