Been slowly sorting out the dash/gauge wiring on my 74. I noticed a couple of things..

1. Turn signals blink on either left or right but the tach signal light sometimes blink once then stop while the outside light continue to blink until I switch off. When I pull hazard, both tach signal light and outside lights blink. Btw, when ignition off, switching on either side will illuminate the markers steadily. I think this last detail is normal?

2. Outside signal front lights have different intensity.. the right front signal light is much brighter than the left. Front side marker intensity are equal. All bulbs and connectors look ok. Rear signal lights are equal intensity.

Does this mean there’s a light bulb that’s not grounded properly? Could there be a short although fuses are ok/intact. Maybe the relay is faulty vs. faulty signal stalk switch or wiring? I haven’t checked the latter since I may need to remove the knee pad to access.

It is normal for the turn signal to turn on the outside marker light steady if activated when the ignition is off. Nor sure why it would blink only once but work normal on emergency flasher mode.
The way to check the lamps for different intensity is to swap the lamps and see if the problem follow the light bulb. Start with the easy fixes first.

As I understand it, the constant on turn signal was a TUV requirement for cars parking on the street.

If you pull the lamps, you want to clean up the sockets too. Bad connections in the socket can cause dim output.

De-Oxit spray is a good quick clean for all electrical, light sockets. Sprayed all the rusted light sockets on my 928 and all lights stayed on good.

The tachometer turnsignal indicators blinking once then not is a sign that the secondary coil in the flasher is weak. This is a typical wear item after 50 years. You can either buy another OEM type or buy a new LED-compatible EP26 on the market today. If you go the EP26, you will have to ground pin C2 to pin 31 internally. I do this internal connection on the EP26 flashers that I sell.

The one side brighter than the other: check closely when flashing to see if both filaments are flashing on the dim side. This is characteristic of a missing ground on that side. The socket could be oxidized or some other ground issue.

Get the EP26 from Spoke. Then if you ever switch to LED turn signals, you are ready to go. It works fine with regular turn signal bulbs.

Thanks to all for the recommendations! Will try out each and see if the bulbs or contacts are the culprit. Otherwise, I might get Spoke's flasher.. how much is your EP26 flasher?

Our metal front lamp housings are prone to corrosion around the lamp sockets. Look
closely for proper grounds. Often the boots which are difficult to install were left off.
I'd bet on it.

I sell them for $20. You can always buy yourself and add the wire. I show how to do add the wire on my website.

you have a grounding problem, and/or the wires plugged in improperly where the parking light blinks and the turn signal is working for the parking light

I have been cleaning all tabs, connectors and sockets, with tiny Dremel wire brushes.

Click to view attachment

They do a great job cleaning and polishing connections. Dust mask and eye protection is recommended. It is surprising the amount is corrosion dust is kicks up. Then I use De-oxit to keep it clean.

[quote name='dr914@autoatlanta.com' date='Apr 13 2020, 08:26 AM' post='2803822']
you have a grounding problem, and/or the wires plugged in improperly where the parking light blinks and the turn signal is working for the parking light

Not sure what you meant George, but I think you and others are correct that it may be a ground issue. Swapped bulbs. Same outcome. I cleaned all the bulb terminals. All the connectors/wires in the back of lamps are secure but I may get some Deoxy-It and spray each connector in the back. The rubber covers are mostly ripped apart. If that all fails, I dont know how to find the grounding issue. Last option is to replace the relay as Spoke recommended.

Last detail I noticed is that the left front (not side marker) bulb only has one of the double filaments lighting up while the right one (which is brighter as I mentioned) has both filaments lighting up.

What is the normal lighting pattern? Is the front park lights not supposed to blink and only the side lights blink when turn signal is activated (with ignition on)? I think this is what George was alluding to. If that's the case, then the wiring is totally messed up! I may need a diagram of the connectors in the back to compare.

Update on this query. Looks like everyone was correct. Wiring was on the wrong terminals on the left front signal light. This fixed the uneven brightness and also the blinking side markers. Tach turn signal light was still intermittently blinking which was fixed by replacing with a new EP26 relay with Spoke's wiring mod. Now everything works! Thanks to all!

Now, the more difficult task of replacing the ripped rubber boots is next (there was a recent thread on this). Or the unlit parking brake light (I think there was recently a thread on this as well).

I bought an EP 26 flasher relay and grounded the C2 to 31 as you say. Turn signals and emergency flashers work, but no illumination indicator. With the old stock relay I'd get a single indicator lite on one side only. What's up ?? I don't think the bulb is out but did not check yet.
Barefoot