Turn signals don’t work after having speedo bezel out.

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Joined
Sep 2, 2012
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Location
Blue Springs, MO
My Car
1971 Mach 1, Grabber Blue w/Argent stripes. Original 2V 351C Auto, Tilt, rear defog, Black Comfortweave Interior. Under restoration. Original colors, 4V 351C, 4-Speed, Spoilers, Magnums, Ram Air. All Ford parts.
Well it’s one step forward and one step back.  
 

Pulled the dash cluster to fix the speedo cable.  Everything was working before tear down, no I don’t have turn signals.  I have not checked the fuse panel yet,  but I would like some ideas on what could have made them stop working before I put everything back together.

I did notice on the speedo cluster flex circuit that 2 of the copper traces were coming loose from the backing Mylar at the connector interface,  I tried to make sure I was careful with the connector, but I am wondering if one of those is not right.  I don.t know if that would affect the entire turn signal circuit or not either.

Another funny thing is the fact that my backup lamp switch came loose.  Looks like the nuts backed off and got lost.

I appreciate any help.  I don’t want to pull the cluster any more than I have too.

kcmash

 
The whole system.  
 

Another thought.  I had to cycle the tilt column up and down several times in the process to get the cluster out and my fat a$$ in the car.

Wondering if something went wrong there.

kcmash

 
Thanks for the help and the good questions Mike and Don.

A couple quick tests and more information.

First, the car starts, runs and drives just fine.  So I feel the column connector is still in good shape.

Tested the horn and the hazards,  they both work and the dash indicators for the hazards work .  So I can probably button the dash back up.

My thoughts now are that the speedo cluster harness plug may have hit a ground when disconnected, the tilt steering caused a short in the harness, or I knocked the flasher for the turn signals out of wack.  I still need to check the fuse as I think hazard and flasher are on different fuses.

Keep the suggestions coming.  I appreciate all the help.

kcmash

 
The ignition switch and upper column (turn signals, emergency flasher and horn) have different connectors.

Because the horn and emergency flashers function you are right, the problem is likely somewhere else. The turn signal fuse also powers the radio and backup lights. The emergency flasher is powered through a circuit breaker.

 
No, the e-flasher and turn signal flashers are on different fuses.  The radio and backup lights (and the windshield washer pump) share the fuse with the turn signals.

 
So that was another weird thing last night.  I found that the backup lamp switch retaining hardware had vibrated loose leaving the actuator hanging under the car by the wires.

So the fuse is definitely blown as I have no power to the radio either.  Just need to figure out what caused that to blow.

kcmash

 
Probably the backup light switch, one side of it is powered whenever the key is on. Depending on how long it's been hanging the insulation may have gotten damaged, exposing the copper strands.

 
Probably the backup light switch, one side of it is powered whenever the key is on. Depending on how long it's been hanging the insulation may have gotten damaged, exposing the copper strands.
They often get pinched on the transmission.

 
That probably explains it.   
 

A repop backup lamp switch and harness.  It goes through the same firewall tie down clamp as the speedo cable.  So when I changed speedo cables and put that clamp back on I bet I pinched the BU lamp harness and shorted it inside the jacketing.

kcmash

 
That probably explains it.   
 

A repop backup lamp switch and harness.  It goes through the same firewall tie down clamp as the speedo cable.  So when I changed speedo cables and put that clamp back on I bet I pinched the BU lamp harness and shorted it inside the jacketing.

kcmash
Well done for finding it  :thumb: - you're going to love breaking your spine in three places to replace fuses - my back still hurts and I replaced one of mine last year 

 
Yep,

So here is the latest.  The pinching of the wire in the clamp was NOT the problem.

When at a cruise night last week I found that the backup lamp switch had popped out of the retainer and was hanging by the wires.  Well apparently when that happened the wiring laid across the H-pipe and melted through.    I re-wrapped the harness, replaced the fuse, slid the BU lamp switch back in and I have NO confidence this will not happen again.

I think I need to bend the retainer for a tighter bite on the switch and I need the proper wire harness routing for the back up lamp wiring.  Right now if I get a good pop into reverse I feel it will push the switch out of the retainer again.

In other news, the car is running great after my vacuum advance and timing adjustments.

kcmash

 
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