Packard Forum Index » Pre-War (1899-1942)

I have totally rewired my 41 using the wonderful Rhode Island wiring harness. Every bit of wire has been replaced from tip to stern. The car has been running flawlessly for the past couple of years since but last night, going down the road my lights started flickering rapidly. Headlights as well as instrument panel lights.

When this happened, I was on high beam. Upon kicking it down to low beam, the problem resolved itself. Later, after switching back to high beam, it would intermittently start again.

Seems clear enough that it is a faulty dimmer (foot) switch but, why would this cause the instrument panel lights to go on/off as well?

If it is the dimmer switch, two questions:

1. Is there a modern replacement switch I can use in place that would fit tight in? I have found a generic one on eBay called a "DS-40" but can't tell if the screw hole spacing would align:

ebay.com/itm/Headlight-Dimmer-Switch-Sta ... T&_trksid=p2060353.m1438.l2649#rwid


2. I can't recall how to access/remove the dimmer switch! Even though I did it once before during the re-wiring, it seems nearly impossible to access from above or below. Anyone remember how this is done?

Thanks!

My read is that the "flickering" is the circuit breaker cycling. Suitable dimmer switch (Echlin DS 102) should be available at NAPA.

Can't help on the exact switch but the DS-40 is labeled as a universal switch and has holes for two different spacing schemes. In all probability it would work. On Clippers at least the switch is accessed from underneath. There are two screws in the passenger compartment which thread into the switch. Once those are out the switch drops down into a sort of boxed in area that is either reached from directly under or else thru a front or side access opening on the engine side of firewall.

As to why the dash lights also go out it is because the instrument lights and switch is fed from the tail light terminal of the headlight switch. The headlight circuit breaker cycling is what is causing the lights to flicker and since the dash lights also are fed from the breaker they flicker too.

The problem could be the dimmer switch but it could also be a shorted wire or connector coming from the switch. The dimmer switch feeds a wire to the junction block on the left fender which then goes on to both high beams on the headlights. There is another wire from the dimmer switch which goes to the indicator light on the dash panel. If a wire goes thru a hole in the fender to reach the lights and a grommet or clamp is missing the wire could vibrate and get damaged. The insulation on the wire to indicator light socket could have shrunk back at the end and left the center conductor exposed where it can touch the grounded shell.

When you find the access to the switch you might remove the double wire off one of the terminals. That will be the high beam feed to bulbs and indicator light. Then try the lights again. If it still flickers on high it is the switch but if the flickering goes away look for a wiring problem.

Thank you for the great advice and guidance...much appreciated!

If you try removing the wires from the switch and have to loosen the switch for access to the terminals, make sure the switch is remounted or the case is connected to ground in some way before the test so any problem would be evident. If the switch was just hanging in the air when you tried it there would be nothing to short against so a problem in the switch wouldn't show.

Great point...I wouldn't have thought of that. Thank you!