521 Signal/Flasher Assistance

[ehathaway]

Hi all, 

 

Just got my '72 521 back after having some electrical work done to it, but I'm a little stumped with the turn signals. 

 

So, the electrician told me that the signal switch is really worn out. But, the exterior turn signals turn on just fine. However, the interior arrows light up only half of the time, regardless of the exterior signals always working. I'm wondering if it could have anything to do with the flashers? Which look to be very old, and a lot of the information/stamping has faded. I can tell that they are Niles flashers, but it's pretty difficult to make out any other information.

 

Would really appreciate some advice. Happy to provide additional info!

 

Thanks!

[DanielC]

If the exterior lights always work, it is not the turn signal switch.   The flasher has only two connections, and power for the turn signal lights has to go through the flasher, so the flasher either works, and switches the power going through it on and off, or the flasher is either switched on all the time, or never switched on.  If the flasher is constantly switched on, when you move the turn signal lever, the turn signal stays on, until you move the turn signal back to the middle.   If the flasher never switches on, the turn signals will not come on.

 

Here is a picture of the back of the meter.  Again, if the outside turn signal lights all work, and flash, the turn signal switch is good, and so is the flasher.   The most likely cause of the indicators not working is the lamps are bad, or the lamp holder is not making contact. 

 

First thing, what do the pins hook up to.

 

I had to clean the contacts on the circuit board, the contacts in the bulb holders, the bulbs themselves. Here is a picture of one of the lamp holder holes, half cleaned. I used a Scotchbright abrasive pad to clean the contacts. In this picture, one side is cleaned, the other is not.

 

I also had to repair some grounds on the circuit board. the circuit board does not have a full copper trace for the grounds, but uses the metal case, and rivets through the circuit board to complete the grounds. To repair the grounds, I had to bridge the head of rivet to the trace on the circuit board.

 

Then I had to test the combo meter.

Get a 12 volt battery, and hook the negative up to pin 10.

Apply 12 positive to pin 1, the four dash lights should turn on.

Apply 12 positive to pin 2, the left turn light should turn on.

Apply 12 positive to pin 9, the high beam light should turn on.

Apply 12 positive to pin 12, the right turn light should turn on.

 

Apply 12 positive to pin 7, and ground pin 4, the oil light should turn on.

Apply 12 positive to pin 7, and ground pin 8, the IGN (alt) light should turn on.

 

Apply 12 positive to pin 7 and ground pin 10, and also ground pin 3, the fuel gauge should go to full.

Apply 12 positive to pin 7 and ground pin 10, and also ground pin 11, the temp gauge should go to hot.

 

Here is a wiring diagram.

 

By the way, power for the turn signals goes through the ignition switch, and the hazard switch.

[Crashtd420]

Daniel has you on the right track....

I had similar issue.... I would loose ground and the inside signals were dim almost not working... I actually had to solder 2 leads to get the ground signal restored....

[yenpit]

Always replace the old flasher units, both turnsignal AND hazard, with a heavy duty electronic (not just electric like original!) flasher unit!  I use Novita part # EL12 (AutoZone) on ALL of our classic cars & even on a recent Factory 5 Shelby Daytona build in our shop!  It is a direct plug in, they have never failed me & they seem to "power thru" the old original potential wire harness corrosion!

[datzenmike]

All mine are electronic. The wrecking yards are full of cars with them. I have an LED lamp in the back and I doubt the load sensitive ones would even work anyway.

[Draker]

Bi-metallic strip type flashers would probably be very slow with LEDs

[datzenmike]

Paint drying is much faster.