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aspedt2
08-19-2018, 12:41 PM
Turn signals not working correctly. With ignition on, motor off, left and right signals and hazardous flashers work fine. Start up engine hazardous flasher work but no response to either left or right signals. later in the day after several short trips left and right signals work perfect until the next morning when the same thing happens again. What can I do?

RalphP
08-19-2018, 02:01 PM
Turn signals not working correctly. With ignition on, motor off, left and right signals and hazardous flashers work fine. Start up engine hazardous flasher work but no response to either left or right signals. later in the day after several short trips left and right signals work perfect until the next morning when the same thing happens again. What can I do?

Use the EVTM and trace out where it's breaking.

Now - my WAG from out here, not able to test?

Ignition switch.

For better WAGging or even SWAGging, try adding which year your vehicle is. That way someone else with a EVTM can tell you which wire should be what.

RwP

aspedt2
08-19-2018, 04:26 PM
Should I replace the signal flasher relay, if so where is it located under the dash,
1990 Ford T'Bird SC

RalphP
08-19-2018, 11:06 PM
Should I replace the signal flasher relay, if so where is it located under the dash,
1990 Ford T'Bird SC

Did you check the ignition switch yet? Have you obtained a Electrical Vacuum Troubleshooting Manual (EVTM) yet?

I'd not think the flasher module since its failures typically are not ignition-switch-position dependent.

RwP

DrFishbone
08-21-2018, 12:16 PM
Don't mess around with possible ignition switch failures....if your car is 89-92 you could easily lose your brake pressure. :eek:

I'd 2nd Ralph on the ignition switch.

HungerC
01-09-2019, 03:38 AM
With intermittent operation, as described, the culprit is often a poor (cold) solder joint. Since the turn signals and 4-way flasher components are both in the flasher module, that is the likely failure point. Remove the flasher module, open the case, and use a low wattage soldering iron to re-solder each connection to the circuit board. Add flux and solder to make a smooth strong joint and clean the flux after the solder joint has cooled. Test the flasher in the circuit before replacing the module cover, to verify cold and warm operation. Cold solder joints typically are open when cold, but sometimes will close up when warmed up and work properly, until the next cold cycle.

If the problem persists, a replacement electronic relay 5-pin module (EP27) is available for later model vehicles. This module will work with both incandescent and LED lamps (without load resistors). Refer to another article on this forum for replacing and upgrading to the EP27 relay.

The problem may also be a cold solder joint in the ignition switch wiring. A similar procedure to repair a cold solder joint may solve a problem in the ignition switch wiring connector. With the ignition switch open, check for corrosion and oxidation in the moving parts of the switch, since all these components are approaching 30 years old and may just be subject to both electrical and/or mechanical connection failure.

KMT
01-09-2019, 11:39 AM
With intermittent operation, as described, the culprit is often a poor (cold) solder joint.

I don't believe there are any solder connections in the SC's ignition switch. As well, given the low cost, the ease to troubleshoot, and the design which tends to fail over time, if there is any question, a replacement with new is always the proper course of action in this example. AZ wants $16 for a new one.

Ken

RalphP
01-10-2019, 12:42 AM
I'll add that the most common failure AFAIK is that the pot metal tabs that hold the bakelite plate in bend and break ...

But yes, no solder in these.

RwP

KMT
01-10-2019, 12:57 AM
most common failure AFAIK is that the pot metal tabs

Coupled with the non-trivial tension that wants to crack the darn thing open like an oyster, those bad boys don't stand much of a chance, do they. Elegantly designed to fail in 10, 9, 8, 7, 6.... ;)

The solder comment (valid when applies) makes me think someone has been watching too much SMA on 'da youtubes, baby.