Brake Lights/dash lights intermittent

[Logan Robb]

Uh Oh! Took the 64 out for dinner tonight and on the way home after dark, I noticed the dash lights went out. Not being all that familiar with the wiring schematic, I figured I’d better check the break lights/running lights as well. To my dismay, no brake lights, no running lights, no plate lights. Uh Oh!

Good news is we were not far from home. On the way home, everything came back on. This is the first time of this issue that I know of. My initial guess of fuse is not correct I suppose. So to the garage she goes. 

I am wonder where to start? Ground? Broken wire? Headlight switch? 

Thanks all! 

[Logan Robb]

Fuse I will check first. Any idea where the grounds are for dash lights and stop lights?

And to note-plate lights are tied into that circuit too.

[3ft7bqmb7dryo]

There is no common ground for all of the lights, check the body feed fuse and the condition of the fuse clips. 

[Logan Robb]

I tried to clean as many grounds as I could today. 

I believe I have narrowed it down to either the body feed (fuse is good) but clips could be corroded. 

Next option is the headlight switch, but I have jiggled this around SIGNIFICANTLY and it did not make the lights go out at all. 

I spent about 20 min testing the brake switch and the light switch while the lights were working, switch didn’t seem to cause any issues.

But the lights are still intermittent. Sometimes the work, sometimes they don’t. 

Tomorrow I’m cleaning the fuse block and see if that fixed the issue. 

Logan

[Jason Edge]

My 64 CDV will often sit for long periods of time and sometimes when I drive it the dash lights will flicker or not even come one. It is definitely my headlight switch for me as I just push and pull and turn the control knob they will stop doing it. I have also sprayed some electrical cleaner (e.g. tuner lube) into the shaft as I work it and they seemed to stop the issue permanently. It did not affect running lights, headlights, etc. so you may have other issues. Check all the connections at the fuse box, feed to the headlight switch, etc. 

[Jason Edge]

The headlight switch, like most components on the dash gets ground from the instrument panel cluster and metal dash itself.

For 1964:
There is an attaching spanner nut beneath the chrome collar that pulls out that tightens the switch on non-Guidematic equipped cars. Make sure that nut is tight. You can pull the control knob & rod all the way out (headlights on mode) and pull the chrome collar back to see the nut and probably get access  with bent needle nose to tighten without removing control knob & rod. 

For Guidematic equipped cars there is a knob and sleeve that simply tightens up against the instrument cluster. With control knob and rod removed you can tighten with an Allen wrench.  You can also just take you hand and turn clockwise tight to give a pretty good connection.

This is in your 1964 Shop manual under Headlight Switch removal and installation starting on page 15-6.

Also, just for clarification, the Tail & Stop lights, Ash Tray lights, cornering lights, courtesy lights, ignition switch lights, and instrument cluster lights are all fed from Tail and Stop Lights fuse, not the Body Feed Fuse. See page 12-97 in 1964 Shop Manual for Fuse chart. 

[Logan Robb]

Interesting. I will have to see if my Corning lights are functional. 

[Logan Robb]

This would be a good warning system. 

I will have to keep the group updated on a brake light project I'd like to complete before the summer is up. 

I really would like to add a 3rd brake light. I know there are a lot of people that want to keep their cars original, and I certainly agree....to a point. But for me personally, I think any upgrade you can make that will influence the safety of the vehicle in a positive way is a must. 

I have posted this project idea to some of the Facebook groups and caught more backlash than anticipated, not that it really bothers me, but I am hopeful that this group of individuals will be a little more understanding of my thought process with this. 

Once I get some of the parts in, I may start a blog thread. Based on my results, it may persuade others to try and complete the same task. I hate for myself- or anyone else- to be involved in a rear-end accident because of something as simple as a 3rd brake light. Yes, I know we all carry insurance (I work in insurance claims myself), but that doesn't mean the claim-handling process will yield a repaired car. Most likely the opposite. And I intend to keep my car until I am 6ft under!

Anyway, all that to say, if you have any good ideas as to how to elegantly implement a 3rd brake light into a car that was not designed to have one, I am all ears. 

Logan

[Patrick Westphal]

Logan,  I have experience in this - electrical work is what I spent my career doing at Cadillac Engineering.  I took a look at the schematic for our cars and here are some facts.  There is no fuse to check for the lighting circuit.  The headlights/taillights, dash lights, are all protected by a circuit breaker inside the headlight switch.  There is also no single ground location for all of those lights, so your issue is probably not caused by a dirty ground location.  That being said, cleaning the ground locations is an excellent idea on our 60 year old cars.  See the Help section on our website, Jason has done a great job in describing the ground locations with pictures.  OK so what is the probable cause here?  All of the lights that you are talking about get their 12 volts from the headlight switch.  That says the probable cause of your problems is either an intermittent connector to your headlight switch of the headlight switch itself.  The other possibility is an intermittent connection from the red wire that comes off the side of the fuse block and goes directly to the headlight switch.  Please keep us all informed and good luck.  

[Logan Robb]

Thank you for this! This is the kind of stuff that makes the forum so useful! 

See my update below, I think I have it sorted at this point but I will continue to monitor daily, or as often as I have the car out, to make sure this issue does not rear its ugly head again. 

[Patrick Westphal]

Mark - good catch and I stand corrected.  That's what I get for looking at a colorized schematic of a 1963 Series 62 convertible.  They changed the 12 source for the stop lamps between the two years.  The 1963 stop lamps are sourced from a Pink/white wire off of a 14A Turn Signal Fuse, while the 1964 stop lamps are sourced from a 25A Tail Lamp fuse.  Either way neither model year is sourced from the headlight switch. 

[Logan Robb]

Thanks all for this! I believe it was indeed the fuse clips being corroded. 

I should have found a way to measure the light output before the clips were cleaned to after to see if a cleaner connection leads to a brighter light. 

Personally, I can't really tell. A night, the lights are as bright as can be! But in the daytime, the sun tends to wash them out. I have never had the chance to follow my car during the day, but I would venture to say the stop lights are virtually invisible in the daytime. I would love to hear if anyone has a remedy for this without modifying it too much. I have a potential project that could assist with visibility during the day, but I still would like brighter tail lamps for day time use as this is when I drive the car most. See my post above about a 3rd brake light

Logan

[Logan Robb]

A good question about the circuit breaker. I wonder if it will reset itself after it gets too warm. 

Logan