Turn Indicator Issue

[Rich in Colorado]

I have a 1958 Fleetwood, Sixty Special.  When turning on the left or right turn indicator, both lights in the dash blink.  The manual says it will do this when a blub is out, something wrong with the circuit.  All lights work.  The flash rate is correct, (not flashing real fast or slow).  I checked all bulbs and they are the correct per the service manual.  I tried a new flasher.

I am pretty good with things electrical so this "simple" circuit is driving me crazy.  Any thoughts?

Thanks,
Rich in Colorado

[cadman56]

I know this sounds crazy, but could it be the flasher unit?  Larry

[Jon S]

I have a 1958 Fleetwood, Sixty Special.  When turning on the left or right turn indicator, both lights in the dash blink.  The manual says it will do this when a blub is out, something wrong with the circuit.  All lights work.  The flash rate is correct, (not flashing real fast or slow).  I checked all bulbs and they are the correct per the service manual.  I tried a new flasher.

I am pretty good with things electrical so this "simple" circuit is driving me crazy.  Any thoughts?

Thanks,
Rich in Colorado

When both dash indicators are flashing are the front/rear lights on the left or right turn only blinking or do both sides blink. e.g. Do the turn signals function correctly and only the indicators have a problem or do all four external bulbs blink together?

[Dan LeBlanc]

Which year had the one year only printed circuit on the back of the speedometer?  Was it 58 or 59?

[Jon S]

1958 has a PC board for sure

[Dan LeBlanc]

That could be the problem if all else is fine. 

[J. Gomez]

Rich,

Once of the biggest issues with the Cadillac using the 3-prong flasher is the way the “P” side is wire between both instrument cluster directional lamps.

Outside from what the manual states bad or wrong type of bulbs front, rear or cluster panel ones and/or flasher unit, when both “L” and “R” are on when you turn the signal switch to either side one possibility is a bad/lose ground from the front signal lights.

The “P” side of the flasher is wired to both “L” and “R” side instrument cluster signal indicators, this provides the intermittent +12V to them. Now the ground for these are pick from the opposite side of the front signal light bulb filament to ground.

So if you turn the turn signal indicator to the “R” side the ground source for the cluster “R” indicator would be from the “L” front bulb filament to ground and vice-versa.

It is hard to explain in plain words and it took me a few trial to figure the arrangement so I made a drawing to get a better picture. 

HTH

[Ed Eckhart #12747]

I had the same issue with a replacement of the flashing unit on my 57. The new one I purchased from NAPA, which was supposed to be a correct replacement for my car, caused both directional signals to flash at the same time. I took it back for a replacement, and it did the same thing. Finally, I ordered an old NOS flasher of off ebay, and it worked perfectly. The 58 is apparently different from the 57, but just my two cents worth.

[jenasp]

I had the exact same problem with my 58 Fleetwood and after a lot of searching it turned out to be the ground for the front turn signals.

[Rich in Colorado]

All,

Sounds like I need to check front grounds.  What Ed said about the flasher is interesting too.  I'll look in to that today and update.  Thanks for the diagram.   Only the dash board lights both flash.  All lights outside, front and back indicate correctly.  Left, only left flashes, right only right flashes.

Rich

[Rich in Colorado]

All,

I spent some time on this issue yesterday.  The diagram from Jose helped a lot to understand the circuit.   The front lamps appear to be properly grounded.  Ohm'ed it all out.  I tried a different flasher.  Checked connectors.  Still have the issue.

I didn't mention before that I have fog lamps.   Does that make a difference?

Rich in Colorado.

[J. Gomez]

All,

I spent some time on this issue yesterday.  The diagram from Jose helped a lot to understand the circuit.   The front lamps appear to be properly grounded.  Ohm'ed it all out.  I tried a different flasher.  Checked connectors.  Still have the issue.

I didn't mention before that I have fog lamps.   Does that make a difference?

Rich in Colorado.

Rich,

If everything checks out ground and flasher one possibility is the cluster indicator bulbs or the front one, although you had checked those already. The cluster would need to be the correct type 1895 with a filament resistance of 52 ohms and the front ones 1034 with a filament resistance of 7 ohms for the directional signal path per the MPL bulb chart.

If the bulbs are the wrong type i.e. lower filament resistance there would be a chance the flashing +12V would bled over to the on providing the path to ground.

Just a hint..!

[Seville1957]

All,

I spent some time on this issue yesterday.  The diagram from Jose helped a lot to understand the circuit.   The front lamps appear to be properly grounded.  Ohm'ed it all out.  I tried a different flasher.  Checked connectors.  Still have the issue.

I didn't mention before that I have fog lamps.   Does that make a difference?

Rich in Colorado.

Rich,

please share your solution when you correct this, I'm having the same problem with my 57' Eldorado.

[Rich in Colorado]

Ed you were right.

My Son-in-law also has a 58 Sixty Special that works correctly, so I took his flasher and two front lamps out to try them.  The flasher fixed the problem.  His flasher has the same part number (550) as both of mine, but his works.  I ordered a NOS from a Ebay seller and expect that to work.  If it doesn't I'll repost.

BTW, I broke one of his fog lamps getting it out.  This would be really bad as the Cadillac part suppliers charge $40 to $50 a bulb for a 1044 lamp.  I found that replacemenlightbulbs.com (http://www.replacementlightbulbs.com/index.html) sells them for $5.  I ordered a lifetime supply (4) that cost less with shipping than most charge for the bulb.

Thanks to all for the help,

Rich

[Ed Eckhart #12747]

The part number for the NOS flasher I had that worked is P273D. The 550s from NAPA did not work.

Ed