Dim Dash Lights - '65 Chrysler 300

[rexus31]

I've noticed my dash lights dim quite substantially while at idle then illuminate back to normal at cruise RPM's. Any idea what could be causing this?

 

[detmatt]

Check your voltage regulator.

 

[rexus31]

Check your voltage regulator.

Thanks.

The main one under the hood or the one on the cluster?

 

[detmatt]

Thanks.

The main one under the hood or the one on the cluster?

Main under the hood.

 

[rapidtrans]

I just replaced mine with an electronic regulator purchase from FuryGT at Carisle. More than the light dimming I use to loose radio reception at idle. My am radio had trouble pulling in CKLW from Windsor. The only oldies on am around here. It improved the idle drop but couldn’t help me with all the overhead power wire interference.

 

[detmatt]

I just replaced mine with an electronic regulator purchase from FuryGT at Carisle. More than the light dimming I use to loose radio reception at idle. My am radio had trouble pulling in CKLW from Windsor. The only oldies on am around here. It improved the idle drop but couldn’t help me with all the overhead power wire interference.

Same here but I ended up using a mid ‘70s Mopar piece I had in stock here, a huge improvement over the old mechanical units.

 

[rexus31]

Thanks guys. I've been running a solid state unit for years. Maybe it's finally giving up. I'll swap it out and see if it helps.

Thanks, again.

 

[Ross Wooldridge]

Typically it's the alternator not outputting as much at idle - for various reasons. While I don't expect your car has issues with the bulkhead, that's mostly where the losses occur, so have a look to see that there are no issues. Once all the connections are deemed good, you can look to increase alternator output at idle.

I got the slightly smaller diameter pulley (usually cad plated) on mine that was used for heavy electrical spec cars (police/taxi etc) that helped some, and then I'm going to use the adjustable voltage regulator spec'd for the same use. FWIW, my Monaco was originally equipped with this unit and the heavy duty 59 amp alternator - but over the years a standard V reg was substituted.

The great thing about that V reg is that you can bump up the idle output from the alternator with this unit. Spec'd for use with Leece Neville equipped cars AND in heavy electrical spec cars with high output standard alternators (59 amp as opposed to standard issue 37 amp).

Typically mounted on the inner fender on a special bracket rather than on the firewall (see my engine bay pic). Often seen on Imperials, but seen on C bodies with lots of options...

 

[1970cat]

is your idle speed correct?

 

[Mike66Chryslers]

You could also have a phase out in your alternator, usually because of a dead diode.

 

[twostick]

You could also have a phase out in your alternator, usually because of a dead diode.

Pulsing lights is the tell tale for that.

Kevin

 

[rexus31]

Thanks guys. I've got a new Voltage Regulator on the way so I'll start with that. If that doesn't resolve the issue, I'll have the Alternator tested.

 

[twostick]

Have you bypassed your ammeter? All the power goes through there first. If the connections there are getting crusty it will create resistance which would dim your lights. Also the heat generated could burn your car down.

On later model cars, the resistance at the ammeter can actually cause a no charge condition with factory solid state regulators.

Kevin

 

[rexus31]

Have you bypassed your ammeter? All the power goes through there first. If the connections there are getting crusty it will create resistance which would dim your lights. Also the heat generated could burn your car down.

On later model cars, the resistance at the ammeter can actually cause a no charge condition with factory solid state regulators.

Kevin

I have not bypassed the Ammeter. I'll check the connections at the bulk head and Ammeter. When I restored the car I used all new wire from the firewall forward and all other connections were cleaned and in good working order. I doubt that is my issue but I will check it nevertheless. Thanks for pointing it out.