No instrument panel lights

[CadDad]

  I am trying to figure out why I have no instrument panel lights. I recently bought my 55 series 62 Cad and have a few odd items to work out. The previous owner told me that all the bulbs must be burnt. I thought that would a little unlikely so I replaced a couple with good ones and they didn't light. I do have lights for oil and generator warnings. I also have lights outside (park ,high and low beam). Before I pull the light switch to examine ,I would like a suggestion or two on what to do or what I may be missing. I'm not too mechanically inclined and tearing into things is a little daunting. My shop manuals really don't have much in the way of trouble shooting. Many thanks in advance.   Paul

[Bill Balkie 24172]

Hello Paul ,
  I had the same problem with my 1957 . The headlight switch is a little involved to remove , But my problem was the restate on the pull switch itself . it was very corroded . so bad the coils were deteriorated , I could put a jumper on the restate ,and the lights would be on all the time . But i wanted to control the lights . iIwanted the switch to work the way it was supposed to . i found a very good switch on ebay and it was like new , i paid about 100.00 for it .  and i was glad to get it . and the switch worked perfectly . but not having the dash lights  really bothered  me . I found out this is a very common problem . if you do not mind the lights just staying on without any control .  you could just jump the wire on the switch . Good luck .

  Bill

[quadfins]

I concur with Bill.

I suspect something amiss with the main power feed to the instument lights. It is very unlikely that all the bulbs would happen to burn out at the same time, and your test with new bulbs indicates there is a lack of power, not bad bulbs. Try bypassing the switch and seeing if the lights all come on. Then you can work your way back to see if it is a faulty rheostat, or a bad connection at the main switch.

All the other lights you mention are on different circuits. Power is getting to and going through the switch to them, so the impasse is somewhere in the vicinity of the rheostat.

Jim

[CadDad]

 Thanks Guys,
    That looks like my next route!!!

[Glen]

Before you go taking everything apart, have you tried rotating the headlight switch knob? 

You probably know this is the control that controls the brightness of the dash lights and turns them off.  If you still have problems rotate the know back and forth several times this will help clean any corrosion off the windings of the rheostat.  That could save you a lot of work removing the switch. 

Glen

[CadDad]

 Thought I would follow up on this topic. I got a NOS switch on ebay and installed it today. Vola!! Dash lights. You guys were right. Corroded rheostat. Thanks 

[Brian Daum]

But you would have saved yourself the work with changing the light switch if you did what Glen suggested.

Corroded rheostat is a common problem. I usually sit down with a cup of coffee, rotate the switch gently back and forth, and suddenly the light comes on.

But having a new light switch I suspect your dashlight are pretty bright?

[David King (kz78hy)]

On my 58, the 2 electric contact points on the ceramic rheostat were corroded/broken where it makes contact the bakelite housing. I was able to solder on a couple of tabs to replace the missing sections. While is was out, I sprayed some contact cleaner on the coiled wire .

I compared the switch I removed with 2 others I had in my spare parts boxes, and both of those had the same issue. So I assume this is a common issue with this style of switch.

The switch is pain to disassemble and reassemble due to those pesky contact springs at the rear of the switch. Make sure you work in a clean and light area so you can find those little springs when the pop out. This caused the profanity center of the brain to be well stimulated after the 3rd or 4th time.

Once installed back to the car, it worked as it should and that was cool.

David

[CadDad]

 I did rotate the switch for quite some time and never got any response. I also noticed the NOS replacement rheostat is a little larger with a heavier coil. 

[Glen]

Yes that is also a common mode of failure for the rheostat. The wire coil separates from the end pieces or the wiper warps and no longer makes contact. 

You always try the cheapest/easiest thing first. 

I’m glad you got it working.

Glen