Author Topic: What continuity 66 Mustang electrical plugs - troubleshooting  (Read 512 times)

Offline jkasavan

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What continuity 66 Mustang electrical plugs - troubleshooting
« on: November 17, 2023, 08:34:38 PM »
1966 289 V8 2bbl Convertible and working on electrical issue - no turn signals working. Fuses all good. Installed new turn signal switch because - in left turn position, found short from blue wire 44 to the turn lever metal, however, this didn't fix problem. So I checked for short/continuity in the main connector plug and firewall plug. Which connectors should have continuity to ground? And - which should not? See my primitive drawings. Thanks!!
« Last Edit: November 19, 2023, 06:12:22 PM by carlite65 »

Offline midlife

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Re: What continuity 66 Mustang electrical plugs - troubleshooting
« Reply #1 on: November 18, 2023, 12:06:24 AM »
With no bulbs in any headlights, tail lights, parking lamps, you should not see any continuity from any plug you describe to ground.Be aware that you should not use the sound feature of a DVM for measuring continuity, particularly as it will beep if there is a bulb in the circuit (bulbs have about 1 ohm of resistance).  I suspect you measured continuity with bulbs in the circuit.

The only ground wire is for the constant voltage regulator on the back of the dash cluster.  The entire chassis is grounded by a lead from the passenger side rear head to the firewall.  There are ground wires for the front marker lamps, headlamps, and tail lights, but they are near those devices and plug into the chassis.  Similarly, the license plate lamp has a separate ground wire. 
« Last Edit: November 19, 2023, 06:13:38 PM by carlite65 »
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Offline jkasavan

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Re: What continuity 66 Mustang electrical plugs - troubleshooting
« Reply #2 on: November 19, 2023, 05:13:16 PM »
Thank - I think I burned out the new turn signal flasher. When I put a jumper on the wires to the turn signal flasher, I got steady light on. So, I tried the old turn signal flasher that I still had and now I have turn signal everywhere except left rear. But left rear does work for brakes and headlights.
« Last Edit: November 19, 2023, 06:14:01 PM by carlite65 »

Offline midlife

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Re: What continuity 66 Mustang electrical plugs - troubleshooting
« Reply #3 on: November 20, 2023, 01:28:56 PM »
Brake and turn signals are combined on one line; running rear lights (when headlights are on) are on the other line.
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